Transcript
ARIB STD-T53 C.S0017-007-A v1.0 Data Service Options for Spread Spectrum Systems: Analog Fax Service
Refer to "Industrial Property Rights (IPR)" in the preface of ARIB STD-T53 for Related Industrial Property Rights. Refer to "Notice" in the preface of ARIB STD-T53 for Copyrights
1
Original Specification
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This standard, ARIB-T53-C.S0017-007-A v1.0, was prepared by 3GPP2-WG of Association of
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Radio Industries and Businesses (ARIB) based upon the 3GPP2 specification, C.S0017-007-A
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v1.0.
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6
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Modification to the original specification None.
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Notes
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None.
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3GPP2 C.S0017-007-A Version 1.0 Date: June 11, 2004
Data Service Options for Spread Spectrum Systems: Analog Fax Service
© 3GPP2 2004 3GPP2 and its Organizational Partners claim copyright in this document and individual Organizational Partners may copyright and issue documents or standards publications in individual Organizational Partner's name based on this document. Requests for reproduction of this document should be directed to the 3GPP2 Secretariat at
[email protected]. Requests to reproduce individual Organizational Partner's documents should be directed to that Organizational Partner. See www.3gpp2.org for more information.
© 3GPP2 2004
C.S0017-007-A v1.0 CONTENTS 1
1
INTRODUCTION ....................................................................................................... 1-1
2
1.1
General Description............................................................................................ 1-1
3
1.2
Terms.................................................................................................................. 1-1
4
1.3
References .......................................................................................................... 1-3
5
2
REQUIREMENTS FOR THE FAX PROTOCOL STACK............................................... 2-1
6
2.1
Overview ............................................................................................................. 2-1
7
2.2
The Application Interface.................................................................................... 2-2
8
2.3
Transport Layer .................................................................................................. 2-6
9
2.4
Network Layer..................................................................................................... 2-8
10
2.4.1
General Requirements ................................................................................... 2-8
11
2.4.2
Assignment of Network Address .................................................................... 2-8
2.5
12
Data Link Layer .................................................................................................. 2-9
13
2.5.1
Sub-Network Dependent Convergence Function ........................................... 2-9
14
2.5.2
PPP Layer ....................................................................................................... 2-9
15
2.5.3
IPCP ............................................................................................................. 2-10
16
2.5.4
Link Control Protocol ................................................................................... 2-10
17
3
REQUIREMENTS FOR THE RADIO INTERFACE ...................................................... 3-1
18
3.1
Service Option Number ...................................................................................... 3-1
19
3.2
Multiplex Option Interface.................................................................................. 3-1
20
3.3
Procedures Using Service Negotiation ................................................................ 3-1
21
3.3.1
Mobile Station Requirements......................................................................... 3-1
22
3.3.2
BS/MSC Requirements.................................................................................. 3-3
23
4
REQUIREMENTS FOR UM INTERFACE CALL PROCESSING................................... 4-1 4.1
24
Connection Establishment ................................................................................. 4-1
25
4.1.1
Mobile Origination ......................................................................................... 4-1
26
4.1.2
Mobile Termination ........................................................................................ 4-2
27
4.1.3
Service Option Change to Analog Fax Service................................................ 4-3
28
4.1.4
Conversation Substate................................................................................... 4-4
29
4.1.5
Traffic Channel Handoff ................................................................................. 4-5
30
4.2
Connection Release ............................................................................................ 4-5
31
4.3
Authentication.................................................................................................... 4-6
32
5
MOBILE PROCEDURES ........................................................................................... 5-1 i
C.S0017-007-A v1.0 CONTENTS 5.1
1
Mobile Receiving Fax.......................................................................................... 5-3
5.1.1
2
Mobile Connecting State................................................................................ 5-3
3
5.1.1.1
Wait for Local DIS Substate ...................................................................... 5-3
4
5.1.1.2
Wait for Remote DCS Substate.................................................................. 5-4
5
5.1.1.3
Wait for Local CFR/FTT Substate ............................................................. 5-4
6
5.1.2
Image Transfer State...................................................................................... 5-5
7
5.1.3
Post Image Transfer State .............................................................................. 5-6
8
5.1.3.1
EOP Substate ............................................................................................ 5-7
9
5.1.3.2
MPS Substate............................................................................................ 5-7
10
5.1.3.3
EOM Substate ........................................................................................... 5-7
5.2
11
Mobile Transmitting Fax .................................................................................... 5-8
5.2.1
12
Mobile Connecting State................................................................................ 5-8
13
5.2.1.1
Wait For Remote DIS Substate.................................................................. 5-8
14
5.2.1.2
Wait For Local DCS Substate .................................................................... 5-9
15
5.2.1.3
Training Substate.................................................................................... 5-10
16
5.2.2
Image Transfer State.................................................................................... 5-11
17
5.2.3
Post Image Transfer State ............................................................................ 5-11
18
5.2.3.1
EOP Substate .......................................................................................... 5-12
19
5.2.3.2
MPS Substate.......................................................................................... 5-12
20
5.2.3.3
EOM Substate ......................................................................................... 5-12
21
5.2.3.4
Disconnect Substate ............................................................................... 5-12
5.2.4
22
Flags ............................................................................................................ 5-12
23
5.2.4.1
Transmitter Trained Flag......................................................................... 5-12
24
5.2.4.2
Receiver Trained Flag .............................................................................. 5-12
5.2.5
25
Rates............................................................................................................ 5-12
26
5.2.5.1
Receiver Rate........................................................................................... 5-12
27
5.2.5.2
Transmitter Rate ..................................................................................... 5-12
28 29 30
6
IWF PROCEDURES .................................................................................................. 6-1 6.1
Mobile Receiving Fax.......................................................................................... 6-3
6.1.1
IWF Connecting State .................................................................................... 6-3
31
6.1.1.1
Wait For Remote DIS Substate.................................................................. 6-3
32
6.1.1.2
Wait For Local DCS Substate .................................................................... 6-4 ii
C.S0017-007-A v1.0 CONTENTS 6.1.1.3
1
Training Substate...................................................................................... 6-5
2
6.1.2
Image Transfer State ...................................................................................... 6-6
3
6.1.3
Post Image Transfer State .............................................................................. 6-7
4
6.1.3.1
EOP Substate ............................................................................................ 6-7
5
6.1.3.2
MPS Substate ............................................................................................ 6-7
6
6.1.3.3
EOM Substate ........................................................................................... 6-8
7
6.1.3.4
Disconnect Substate ................................................................................. 6-8
6.1.4
8
Flags .............................................................................................................. 6-8
9
6.1.4.1
Transmitter Trained Flag ........................................................................... 6-8
10
6.1.4.2
Receiver Trained Flag ................................................................................ 6-8
6.1.5
11
Rates .............................................................................................................. 6-8
12
6.1.5.1
Receiver Rate ............................................................................................. 6-8
13
6.1.5.2
Transmitter Rate........................................................................................ 6-8
6.2
14
Mobile Transmitting Fax..................................................................................... 6-9
6.2.1
15
IWF Connecting State .................................................................................... 6-9
16
6.2.1.1
Wait for Local DIS Substate....................................................................... 6-9
17
6.2.1.2
Wait for Remote DCS Substate................................................................ 6-10
18
6.2.1.3
Wait for Local CFR/FTT Substate............................................................ 6-11
19
6.2.2
Image Transfer State .................................................................................... 6-12
20
6.2.3
Post Image Transfer State ............................................................................ 6-13
21
6.2.3.1
EOP Substate .......................................................................................... 6-13
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6.2.3.2
MPS Substate .......................................................................................... 6-13
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6.2.3.3
EOM Substate ......................................................................................... 6-13
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7
MESSAGES .............................................................................................................. 7-1 7.1
Messages Over the Analog Interface ................................................................... 7-1
26
7.1.1
V.21 Messages ............................................................................................... 7-1
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7.1.2
Image Data..................................................................................................... 7-1
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7.1.3
IWF Identification and Capabilities Messages................................................ 7-2
29
7.1.3.1
IWF NSF and IWF NSC Messages .............................................................. 7-2
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7.1.3.2
IWF NSS Message ...................................................................................... 7-4
31
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7.2 7.2.1
Messages over the Um Interface ......................................................................... 7-7 Control Messages........................................................................................... 7-7 iii
C.S0017-007-A v1.0 CONTENTS 1
7.2.2
Data Message................................................................................................. 7-8
2
7.2.3
Preamble Message ......................................................................................... 7-9
3
7.2.4
Max Rate Message ....................................................................................... 7-10
4
7.2.5
Start CED Message ...................................................................................... 7-12
7.3
5
7.3.1
6
Bit Format of Octets .................................................................................... 7-13
7.3.1.1
7
7.3.2
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Formatting octets over the Um interface .......................................................... 7-13
8
Byte Escaping of Flags................................................................................. 7-13
CALL FLOWS............................................................................................................ 8-1 8.1
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Control, Preamble, Max Rate, and Start CED Messages.......................... 7-13
Call Set-Up ......................................................................................................... 8-1
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8.1.1
Calls Originating as Analog Fax .................................................................... 8-2
12
8.1.2
Calls Originating as Voice, then Transitioning to Analog Fax ....................... 8-4
8.2
13
IWF and MT2 Procedures During Conversation State ........................................ 8-8
14
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TIMERS .................................................................................................................... 9-1
15
10
DIS/DTC MODIFICATIONS.................................................................................... 10-1
16
11
AT COMMAND PROCESSING ................................................................................ 11-1
17
11.1
General Requirements...................................................................................... 11-1
18
11.2
Basic AT Command Processing ........................................................................ 11-1
19
11.2.1
Action Commands..................................................................................... 11-1
20
11.2.2
Basic Result Codes ................................................................................... 11-2
21
11.3
AT Command Set Extensions for Modem Control ............................................ 11-3
22
11.4
Cellular AT Command Processing .................................................................... 11-3
23
11.4.1
AT+CVF Command Processing.................................................................. 11-3
24
11.4.2
AT+CVFQ? Command Processing ............................................................. 11-4
25
11.4.3
AT+CFG Command Processing ................................................................. 11-4
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C.S0017-007-A v1.0 FIGURES 1
Figure 2.1-1. The Analog Fax Protocol Stack Architecture............................................... 2-1
2
Figure 5.1-1. MT2 RX Fax Layer States in a Mobile Receiving Fax Call ........................... 5-3
3
Figure 5.2-1. MT2 TX Fax Layer States in a Mobile Transmitting Fax Call ...................... 5-8
4
Figure 6.1-1. IWF TX Fax Layer States in a Mobile Receiving Fax Call ............................ 6-3
5
Figure 6.2-1. IWF RX Fax Layer States in a Mobile Transmitting Fax Call ...................... 6-9
6
Figure 7.1-1. T.30 V.21 Message Format ......................................................................... 7-1
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Figure 8-1. Message and Signal Representation Used in Call Flows................................ 8-1
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Figure 8.1.1-1. Call Set-Up for a Mobile Receiving Fax Call Initiated as Analog Fax ....... 8-2
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Figure 8.1.1-2. Call Set-Up for a Mobile Transmitting Fax Call Initiated as Analog Fax.. 8-3
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Figure 8.1.2-1. Call Set-Up as Voice Transitioning to Mobile Receiving Fax. Voice Call Shown as Mobile-Terminated and Fax Call Detected Using V.21 Preamble Detection.8-4 Figure 8.1.2-2. Call Set-Up as Voice Transitioning to Mobile Receiving Fax. Voice Call Shown as Mobile-Originated and Fax Call Detected Using V.21 Preamble Detection. 8-5 Figure 8.1.2-3. Call Set-Up as Voice Transitioning to Mobile Transmitting Fax. Voice Call Shown as Mobile-Originated and Fax Call Detected Using V.21 Preamble Detection. 8-6 Figure 8.1.2-4. Call Set-Up as Voice Transitioning to Mobile Transmitting Fax. Voice Call Shown as Mobile-Terminated and Fax Call is Detected Using V.21 Preamble Detection.8-7 Figure 8.2-1. Typical Mobile Receiving Fax Call Where the Initial Fax Training Rate from the Transmitting Fax Machine is Supported by the Air Interface ............................... 8-8 Figure 8.2-2. Mobile Receiving Fax Call Where the Initial Fax Training Rate from the Transmitting Fax Machine is Not Supported by the Air Interface............................... 8-9
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Figure 8.2-3. Mobile Receiving Fax Call Where the Receiving Fax Machine Rejects the Initial Training Rate.................................................................................................. 8-10
24
Figure 8.2-4. Mobile Receiving Fax Call Illustrating the Use of Timer T13 ...................... 8-11
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Figure 8.2-5. Mobile Receiving Fax Call with an RTP Response from the RX Fax Machine8-12
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Figure 8.2-6. Mobile Receiving Fax Call Illustrating Polling (the TE2 has a document to send which the PSTN fax machine retrieves) ............................................................ 8-13
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27 28 29 30 31
Figure 8.2-7. Mobile Receiving Fax Call with Corrupted HDLC Frames (corrupted DCS and CFR)................................................................................................................... 8-14 Figure 8.2-8. Mobile Receiving Fax Call with Corrupted HDLC frames and Fax CRP Option (corrupted CFR, MPS, and MCF)............................................................................... 8-15
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C.S0017-007-A v1.0 TABLES 1
Table 2.2-1. IP Type of Service ......................................................................................... 2-3
2
Table 2.2-2. Compression Options................................................................................... 2-5
3
Table 2.2-3. Group 3 Fax Compression Options.............................................................. 2-6
4
Table 3.3.1-1. Valid Service Configuration Attributes for Service Option 20 ................... 3-2
5
Table 3.3.1-2. Valid Service Configuration Attributes for Service Option 21 ................... 3-2
6
Table 5.1.1.3-1. MSLT Resetting in the DCS.................................................................... 5-5
7
Table 6.2.1.3-1. MSLT Resetting in the DCS.................................................................. 6-11
8
Table 7.1.3.1-1. IWF NSF and IWF NSC Message Format ................................................ 7-2
9
Table 7.1.3.1-2. FIF Format for the IWF NSF and IWF NSC Messages............................ 7-3
10
Table 7.1.3.1-3. INFO Field Format for TYPE=0x00 Information Element ....................... 7-4
11
Table 7.1.3.1-4. INFO Field Format for TYPE=0x01 Information Element ....................... 7-4
12
Table 7.1.3.1-5. INFO Field Format for TYPE=0x02 Information Element ....................... 7-4
13
Table 7.1.3.2-1. IWF NSS Message Format ..................................................................... 7-5
14
Table 7.1.3.2-2. FIF Format for the IWF NSS Message.................................................... 7-5
15
Table 7.1.3.2-3. INFO Field Format for TYPE=0x00 Information Element ....................... 7-6
16
Table 7.1.3.2-4. INFO Field Format for TYPE=0x01 Information Element ....................... 7-7
17
Table 7.2.1-1. Control Message Format ........................................................................... 7-8
18
Table 7.2.2-1. Data Message Format ............................................................................... 7-9
19
Table 7.2.3-1. Preamble Message Format ...................................................................... 7-10
20
Table 7.2.4-1. Max Rate Message Format ...................................................................... 7-11
21
Table 7.2.4-2. FIF Values for the Max Rate Message ..................................................... 7-11
22
Table 7.2.5-1. Start CED Message Format ..................................................................... 7-12
23
Table 10-1. Rate Bit Modifications................................................................................. 10-1
24
Table 10-2. MSLT Bit Modification ................................................................................ 10-2
25
Table 11.2.1-1. Basic Action Commands ....................................................................... 11-2
26
Table 11.2.2-1. Basic Result Codes ............................................................................... 11-2
27
Table 11.3-1. IWF to Mobile Station Commands............................................................ 11-3
vi
C.S0017-007-A v1.0
1
1
2
1.1
3
Service Options 20 and 21 provide Analog Group-3 facsimile (abbreviated as “fax” hereafter) transmission on cdma2000® 1wideband spread spectrum systems using the protocols and procedures defined herein.
4 5
INTRODUCTION General Description
10
Service Option 20 provides analog group 3 fax service using a default service configuration including Multiplex Option 1 data rates. Service Option 21 provides group 3 fax service using a default service configuration including Multiplex Option 2 data rates. Other combinations of service configuration attributes are available for these service options through the use of service negotiation procedures.
11
1.2
12
15
Analog Fax Layer. The functional layer in the MT2 or IWF that processes T.30 messages from the fax machine and the over the air messages from the Um interface. In the MT2, the Analog Fax Layer operates between the Um interface to the IWF and the RJ-11 interface to the TE2. In the IWF, the Analog Fax Layer operates between the Um interface
16
to the MT2 and the PSTN interface to the PSTN fax machine.
17 18
AT Command Set. Command set interface between data terminal equipment (DTE) and data circuit terminating equipment (DCE).
19
Analog Interface. Refers to either the RJ-11 loop or the PSTN.
20
Base Station (BS). A station in the Domestic Public Cellular Radio Telecommunications Service, other than a mobile station, used for communicating with mobile stations. Depending upon the context, the term base station may refer to a cell, a sector within a cell, or other part of the cellular system.
6 7 8 9
13 14
21 22 23
Terms
26
BORSCHT. Battery, Over voltage protection, Ringing, Supervision, Coding, Hybrid and Test. It is a collection of signals and controls necessary to operate an analog phone through an RJ-11 interface.
27
BS. See base station.
28 29
BS/MSC. The base station and mobile switching center considered as a single functional entity.
30
CED. Called terminal identification tone (see T.30 4.3.3.2).
31
CNG. Calling Tone (see T.30 4.3.3.3 and T.30 Figure 15).
24 25
cdma2000® is the trademark for the technical nomenclature for certain specifications and standards of the Organizational Partners (OPs) of 3GPP2. Geographically (and as of the date of publication), CDMA2000® is a registered trademark of the Telecommunications Industry Association (TIA-USA) in the United States.
1
1-1
C.S0017-007-A v1.0
1 2 3 4 5 6 7 8
CFR, CIG, CRP, CSI, DCN, DCS, DIS, DTC, EOM, EOP, FTT, MCF, MPS, NSC, NSF, NSS, PIN, PIP, PRI-xxx, TSI, RTN, RTP. These are V.21 signaling messages that are transmitted either by the receiving or transmitting fax machine during a fax call (see T.30 5.3.6). Digital Facsimile. That form of facsimile in which densities of the original are sampled and quantified as a digital signal for processing, transmission, or storage. Error Correction Mode (ECM). A mode of operation for T.30 fax service providing end-toend reliable data transport.
10
Facsimile. The process by which a document is scanned, converted into the electrical signals, transmitted, and recorded or displayed as a copy of the original.
11
Fax. An abbreviation for facsimile.
12
Group-3. Digital Facsimile equipment per ITU-T Recommendation T.4 and T.30.
13
ICMP. Internet Control Message Protocol.
14
IANA. Internet Assigned Number Authority.
15
17
Interworking Function (IWF). An IWF provides the functions needed for terminal equipment connected to a mobile termination to communicate with terminal equipment connected to the PSTN. A physical implementation may include a pool of modems.
18
IP. Internet Protocol.
19
IPCP. Internet Protocol Control Protocol.
20
L. L Interface . The interface between an IWF and BS/MSC.
21
LCP. PPP Link Control Protocol.
22
Mobile Station. A station in the Domestic Public Cellular Radio Telecommunications Service intended to be used while in motion or during halts at unspecified points. Mobile stations include portable units (e.g., hand-held personal units) and units installed in vehicles.
9
16
23 24 25
27
Mobile Termination 0 (MT0). An MT0 is a self-contained data-capable mobile termination that does not support an external interface.
28
Mobile Termination 2 (MT2). An MT2 provides a non-ISDN (Rm) user interface, e.g.,
29
CCITT V series or CCITT X series.
30
Modem Client. The name given to the TCP well-known port used for CDMA analog fax services in mobile stations.
26
31 32 33
Modem Emulation Service. A wireless data service where the mobile termination appears as a standard telephone modem to a data terminal.
35
Modem Server. The name given to the TCP well-known port used for CDMA analog fax services in a BS/MSC.
36
MSC. Mobile Switching Center.
37
PPP. Point-to-Point Protocol.
34
1-2
C.S0017-007-A v1.0
1
PSTN. Public Switched Telephone Network.
2 3
PSTN fax machine. The fax machine or fax modem connected to the IWF through the PSTN.
4
Receiving fax machine. The fax machine or fax modem receiving the fax document.
5 6
RFC. Request for Comments. The generic name of a standard developed by the Internet Engineering Task Force (IETF).
7
RJ-11. The analog interface that connects the MT2 with the subscriber fax machine (TE2).
9 10
RJ-11 Loop Functions. This is the analog interface function between the subscriber fax machine and the MT2. It provides BORSCHT functionality to emulate the PSTN.
11
RLP. Radio Link Protocol.
12
RTC. Return To Control (see T.4 4.1.4). This is a signal that is used to indicate the end of the fax document or page. This signal consists of six consecutive End Of Line (EOL) characters.
13 14
17
RX Fax Layer. The Analog Fax Layer that directly interfaces through an analog interface to the receiving fax machine. For example, when the TE2 is transmitting, the Analog Fax Layer in the IWF is the RX Fax Layer.
18
SNDCF. Sub-Network Dependent Convergence Function.
19
Subscriber Fax Machine. The wireless subscriber’s fax machine or fax modem connected to the MT2 through the RJ-11 interface.
15 16
20 21 22 23
Tandem Call or Tandem Analog Fax Call . A call in which the transmitting fax machine and receiving fax machine are served by either a single IWF containing an analog fax layer or by two distinct IWFs each containing an analog fax layer.
26
TCF. This training sequence is sent through the T.4 modulation system to verify training and to give a first indication of the acceptability of the channel for a fax data rate (see T.30 5.3.6.1.3).
27
TCP. Transmission Control Protocol.
28 29
Terminal Equipment 2 (TE2). A TE2 is a data terminal device (such as a fax machine) that has a non-ISDN user-network interface, e.g., CCITT V series or CCITT X series.
30
Transmitting fax machine. The fax machine or fax modem sending the fax document.
31
33
TX Fax Layer. The Analog Fax Layer that directly interfaces through an analog interface to the transmitting fax machine. For example, when the TE2 is transmitting, the Analog Fax Layer in the MT2 is the TX Fax Layer.
34
Um. The air interface between the MT2 and the BS/MSC.
35
1.3
36
The following standards and 3GPP2 specifications contain provisions that, through reference in this text, constitute provisions to this document. All referenced publications are subject to revision, and parties to agreements based on this document are encouraged
24 25
32
37 38
References
1-3
C.S0017-007-A v1.0
1 2 3
to investigate the possibility of applying the most recent editions of the works indicated below. ANSI and TIA maintain registers of currently valid national standards published by them. 3GPP2 Specifications and SDO Standards 1.
Reserved Physical Layer Standard for cdma2000 Spread Spectrum Systems – Release C
2.
3GPP2: C.S0002-C v1.0 ARIB: CWTS: TIA: TIA/EIA/IS-2000.2-C TTA: TTC:
3.
3GPP2: C.S0003-C v1.0 ARIB: CWTS: TIA: TIA/EIA/IS-2000.3-C TTA: TTC:
Medium Access Control (MAC) for cdma2000 Spread Spectrum Systems – Release C
4.
3GPP2: C.S0004-C v1.0 ARIB: CWTS: TIA: TIA/EIA/IS-2000.4-C TTA: TTC:
Signaling Link Access Control (LAC) for cdma2000 Spread Spectrum Systems – Release C
5.
3GPP2: C.S0005-C v1.0 ARIB: CWTS: TIA: TIA/EIA/IS-2000.5-C TTA: TTC:
Upper Layer (Layer 3) Signaling for cdma2000 Spread Spectrum Systems – Release C
6.
Reserved Data Service Options for Spread Spectrum Systems: Radio Link Protocol
7.
3GPP2: C.S0017.2-0 v1.0 ARIB: CWTS: TIA: TIA/EIA/IS-707.2-A TTA: TTC:
8.
3GPP2: C.S0017-003-A ARIB: CWTS: TIA: TIA-707.03-B TTA: TTC:
Data Service Options for Spread Spectrum Systems: AT Command Processing and the Rm Interface
1-4
C.S0017-007-A v1.0
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ANSI/TIA/EIA-617
Inband DCE Control for Asynchronous DTE-DCE Interfaces
3
EIA/TIA-602
Serial Asynchronous Automatic Dialing and Control.
4
EIA/TIA-615
Extensions to Serial Asynchronous Automatic Dialing and Control.
6
RFC 791
Internet Protocol.
7
RFC 792
Internet Control Message Protocol.
8
RFC 793
Transmission Control Protocol.
9
RFC 854
Telnet Protocol Specification.
10
RFC 855
Telnet Options Specification.
11
RFC 950
Internet Standard Subnetting Procedure.
12
RFC 1112
Host Extensions for IP Multicasting.
13
RFC 1122
Requirements for Internet Hosts – Communication Layers.
14
RFC 1123
Requirements for Internet Hosts – Application and Support.
15
RFC 1144
Compressing TCP/IP Headers for Low-Speed Serial Links.
16
RFC 1166
Internet Numbers.
17
RFC 1191
Path MTU Discovery.
18
RFC 1332
The PPP Internet Protocol Control Protocol (IPCP).
19
RFC 1349
Type of Service in the Internet Protocol Suite.
20
RFC 1570
PPP LCP Extensions.
21
RFC 1661
The Point-to-Point Protocol (PPP).
22
RFC 1662
PPP in HDLC Framing.
23
RFC 1700
Assigned Numbers (most recent version).
24
T.4
Standardization of group 3 facsimile apparatus for document transmission.
5
25
1-5
C.S0017-007-A v1.0
1
T.30
Procedures for document facsimile transmission in the general switched telephone network2.
TSB58
Administration of Parameter Value Assignments for TIA/EIA Wideband Spread Spectrum Standards.
V.17
A two-wire modem for facsimile applications with rates up to 14,400 bits/s.
V.21
300 bits/s duplex modem standardized for use in the general switched telephone network.
V.27ter
4800/2400 bit/s modem standardized for use in the general switched telephone network.
V.29
9600 bits/s modem standardized for use on point-to-point, fourwire leased telephone-type circuits.
V.33
14,400 bits/s modem standardized for use on point-to-point, four-wire leased telephone-type circuits.
V.42bis
Data compression procedures for DCEs using error correction procedures
2
3 4 5 6 7 8 9 10 11 12 13 14 15 16
17
2 All references to the T.30 standard refer to the March 1993 revision.
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2
2
2.1
3
7
This chapter specifies requirements for an analog facsimile service for CDMA wireless systems based on the protocol stack reference architecture shown in Figure 2.1-1. The service is designed to provide fax service over a wireless data link to a group 3 fax machine (TE2). Although actual implementations may vary with respect to specific network elements, functionality available over the air (Um) interface shall be in accordance with the
8
requirements specified in this standard.
4 5 6
REQUIREMENTS FOR THE FAX PROTOCOL STACK Overview
M obile Station TE2
MT2
I WF
Analog Fax Layer
Application Lay er
Analog Fax Layer
App. I nt. TCP
Transport Layer N etwor k Layer
B S/MSC
RJ-11 Loo p Func tio ns
Subscriber Fax Machine
L ink L ay er Relay L ay er
App. Int.
I CMP
ICMP
TCP IP
IP SN DC F I PCP L C P
L C P IPCP SN DC F
PPP
PPP
RL P
RL P
IS-95
IS-95 Um
RJ -11
Relay L ay er
PSTN I nter face
Relay Layer
L
9 10
Figure 2.1-1. The Analog Fax Protocol Stack Architecture
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
The Application Layer consists of the analog fax layer and the associated application interfaces in the MT2 and in the IWF. The application interfaces in the MT2 and in the IWF support a limited set of EIA/TIA standardized modem control commands necessary for call control and together provide an interface compatible with the fax modem emulation functions of the analog fax layer. The Transport Layer consists of Transmission Control Protocol (TCP). TCP (See RFC 793) provides a reliable transport service to all application layer and user data exchanges. The Network Layer consists of ICMP, (see RFC 792) and IP (see RFC 791) protocols to provide network layer transport of modem control and user data over the CDMA air interface. The Link Layer consists of Point to Point Protocol (PPP), Link Control Protocol (LCP), and Internet Protocol Control Protocol (IPCP). PPP (see RFC 1661 and 1662) provides a multiplexed method to carry higher layer protocol data over serial links. LCP (see RFC 1570) provides a mechanism for the Mobile Station and the IWF to negotiate various options provided by PPP. IPCP (see RFC 1332) allows the Mobile Station to request a temporary IP address from the IWF.
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The Relay Layer consists of physical and logical interface functions required to support the link, network, transport and application layers described above. Central to the relay layer is the inclusion of a Radio Link Protocol (RLP) (see Chapter 2) to improve the error characteristics of the wireless link, thereby reducing the need for Transport Layer retransmissions due to lost data. The protocol stack, as specified in this standard, describes a minimal subset of the TCP, IP and PPP protocols for the mobile station. BS/MSC and IWF protocol implementations shall be compatible with mobile stations having the minimal implementation specified herein.
10
2.2
11
In the mobile station, CDMA analog fax services shall include an application interface between the analog fax layer and the transport protocol layer.
12
The Application Interface
14
In the IWF, the application interface shall reside between the analog fax layer and the transport protocol layer.
15
The application interface shall provide the following functionality:
13
16
•
Modem control, as specified in 11.3.
17
•
AT Command processing, as defined in 11.
18
•
Negotiation of air interface data compression.
19
•
Data compression over the air interface (optional).
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
In a mobile station, ANSI/TIA/EIA-617 in-band commands, including any necessary escaping, shall be inserted into data entering the application interface from the analog fax layer as described in ANSI/TIA/EIA-617. Option negotiation commands shall then be inserted, including any necessary escaping, as described below. The resulting data shall be passed to the transport layer. In a mobile station, data entering the application interface from the transport layer shall first be parsed to extract the option negotiation commands and the associated escaping. The resulting data shall be parsed to extract ANSI/TIA/EIA-617 in-band messages (see 11.3). The resulting data shall be passed to the analog fax layer. In the IWF, data entering the application interface from the analog fax layer shall be passed to the transport layer. ANSI/TIA/EIA-617 in-band commands shall then be inserted, including any necessary escaping, as described in ANSI/TIA/EIA-617. Option negotiation commands shall then be inserted, including any necessary escaping, as described below. In the IWF, data entering the application interface from the transport layer shall first be parsed to extract the option negotiation commands and the associated escaping. The resulting data shall be parsed to extract any ANSI/TIA/EIA-617 in band modem control commands (see 11.3). If the IWF application interface is in command state, the resulting data shall be parsed to extract any AT commands (see 11). The resulting data shall be passed to the analog fax layer .
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The application interface for CDMA analog fax services shall comply with the requirements of Sections 2.3 and 2.4 of RFC 1123, with the following modifications: •
An IWF serving multiple users may be treated as part of a single multi-homed host or as independent hosts.
•
The mobile station application interface should specify type of service as described in RFC 1349. The mobile station and the IWF should specify the types of service shown in Table 2.2-1.
4 5 6 7 8
Table 2.2-1. IP Type of Service
9
Service Option
Type of Service
20, 21 (Analog Fax)
Low delay
10 11 12 13 14 15 16 17 18 19 20 21 22
For mobile-originated analog fax calls, the mobile station application interface shall open the transport layer using TCP well-known port 380 (“modem server”) as the destination port. For mobile-terminated data calls, the IWF application layer shall open the transport layer using TCP well-known port 379 (“modem client”) as the destination port. The application interface in the mobile station and the IWF should also support data compression, using the following negotiation protocol.3 To ensure transparency of user data to compression negotiation commands, the sender shall insert an additional octet of value 255 before each data byte of value 255, except for IAC octets that are part of negotiation commands. The receiver shall remove the inserted octets of value 255 and any negotiation commands after decompression. The application interface shall support option negotiation commands in accordance with the requirements of RFC 854, except that only the following commands are required:
23
NAME
CODE
MEANING
24
SE
240
End of subnegotiation parameters.
25
SB (option code)
250
Indicates that what follows is subnegotiation of the indicated option.
WILL (option code)
251
Indicates a desire to begin performing the indicated option.
26 27 28 29
WON'T (option code) 252
Indicates a refusal to perform, or continue performing, the indicated option.
DO (option code)
Indicates a request that the other station begin performing the indicated option.
30 31 32
253
3This protocol is based on the Telnet option negotiation protocol, as described in Internet RFC 854.
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DON'T (option code) 254
Indicates a demand that the other station stop performing the indicated option.
IAC
Interpret as Command.
2 3 4 5 6 7
255
The data compression option shall be indicated by setting the option code to the value shown in Table 2.2-2 for the type of data compression being negotiated.4 Data compression parameters shall be negotiated using the procedure described in RFC 855, and further defined below.
10
If data compression is supported by the IWF, the IWF shall initiate negotiation of data compression by sending a WILL command when the transport layer connection is opened. The mobile station shall respond with a DO or DON’T command.
11
The mobile station shall not initiate negotiation of data compression.
12
If the mobile station responds with a DO command, the IWF shall transmit a subnegotiation (SB) command followed by the requested data compression control parameters. The mobile station shall respond with a subnegotiation (SB) command with either the same parameters, an alternative set, or a DON’T command.
8 9
13 14 15
23
If the mobile station replies with an SB command whose parameters are acceptable to the IWF, the IWF shall send a DO command. If the accepted subnegotiation parameters include a request for forward link compression, the IWF shall compress all applicable data following the DO command. The mobile station shall respond to the DO command with a WILL command. The negotiation process is terminated when the IWF receives the WILL command. If the accepted subnegotiation parameters include a request for reverse link compression, the mobile station shall compress all applicable data following the WILL command.
24
Compression shall be applicable only as follows:
16 17 18 19 20 21 22
25 26 27 28 29 30 31 32 33 34 35
•
For Service Options 20 and 21 , if MMR compression (see ITU-T T.4) is used, it shall only be applied to the actual fax image data being transmitted. If MMR compression is negotiated during transmission of a page, the compression shall be enabled for subsequent pages. If V.42bis is used, compression shall begin with the next full line passed from the application interface to the transport layer. V.42bis compression may be enabled independently in each direction.
If the mobile station replies with an SB command containing parameters not acceptable to the IWF, the IWF shall send a DON’T command. The IWF may re-initiate negotiation at any time. Either side may terminate compression or subnegotiation at any time by sending a DON’T command and shall send uncompressed data following the command. Whenever a DON’T
4These option numbers may overlap Telnet option number assignments. There is no conflict
because compression negotiation is hidden from any Telnet application that makes use of the CDMA async data service.
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command is received, the receiver shall respond with a WON’T command and shall send uncompressed data following the command. When possible, the timing of these commands relative to the decompression process should be chosen to minimize loss of data. If V.42bis compression is negotiated, it shall not be disabled for the duration of the call. Subnegotiation parameters shall be transmitted in the following format. If any octet following the OPTION octet and preceding the next IAC octet has value 255, an additional octet of value 255 shall be inserted. The value of the PARAMETER_LEN field shall not change as the result of such insertion. The receiver shall remove all such inserted octets prior to processing the subnegotiation parameters.
11
Field Name
Size (octets)
IAC
1
SB
1
OPTION
1
12 13
Zero or more occurrences of the following entry: PARAMETER_ID
1
PARAMETER_LEN
1
PARAMETER_VAL
PARAMETER_LEN
14 15
The subnegotiation parameter list shall be followed immediately with: IAC
1
SE
1
16 17
OPTION
-
18 19
Option value. The application interface shall set this field to the value shown in Table 2.2-2 corresponding to the type of compression selected.
20
Table 2.2-2. Compression Options
21
Option
Compression Type
0x00
V.42bis compression
0x01
Modified Modified Read Coding
All other values are reserved. 22 23
PARAMETER_ID
-
Parameter Identifier.
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C.S0017-007-A v1.0 The application interface shall set this field to identify the parameter. All parameters in the subnegotiation command shall be as required for the selected compression option.
1 2 3
PARAMETER_LEN
4
-
The application interface shall set this field to the number of octets in this parameter, not including the PARAMETER_ID and PARAMETER_LEN fields.
5 6 7
PARAMETER_VAL
8
-
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Parameter Length.
Parameter Value. Indicates the desired setting for this parameter.
If negotiation does not occur, the default setting shall apply. The default setting is no compression. If the OPTION field selects V.42bis compression, the parameter entries may be configuration parameters 1, 2 and/or 3 of the compression scheme defined in ITU-T Recommendation V.42bis. For V.42bis compression, these parameters, their identifiers, and lengths, are as defined in V.42bis, Annex A. For negotiation of V.42bis compression, the IWF is always considered the initiator. For each direction of transmission for which V.42bis compression is requested, the compression scheme defined in ITU-T Recommendation V.42bis shall be applied to all data passed from the application interface to the transport layer (excluding option negotiation commands), and the corresponding decompression scheme shall be applied to all data passed from the transport layer to the application interface. If the OPTION field selects Modified Modified Read Coding compression, no parameter entries are defined. When MMR or V.42bis compression is negotiated, it shall only be used in accordance with Table 2.2-3.
26
Table 2.2-3. Group 3 Fax Compression Options
27
Um Compression Method
PSTN Compression Method Modified Huffman
Modified Modified Read or V.42bis
Modified Read
(no additional compression)
Modified Modified Read
(no additional compression)
28
33
If Modified Modified Read compression is negotiated, the compression scheme defined in ITU-T Recommendation T.4 shall be applied only to the fax image data passed from the data source to the application interface layer, and the corresponding decompression scheme shall be applied only to the fax image data passed from the application interface layer to the data destination.
34
2.3
35
The transport layer for CDMA analog fax services is based on the Internet transport layer protocol known as Transmission Control Protocol (TCP), described in RFC 793.
29 30 31 32
36
Transport Layer
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The implementation shall comply with the requirements of RFC 793, as amended by RFC 1122, with the following modifications: •
TCP should always advertise a Maximum Segment Size (MSS), which should be no smaller than 536 octets (which is the default value).
5
•
TCP should limit the transmitted segment size to no more than 2047 octets.5
6
•
TCP should advertise a window size no smaller than twice the advertised MSS, and no larger than 4 times the MSS.
•
For each connection, the transport layer shall use a different source port number than the one used in the previous connection. The port numbers used shall be in the range from 0x1000 (decimal 4096) to 0xffff (decimal 65535), inclusive. The mobile station’s port number may be initialized to an arbitrary value in this range on power-up.
•
The IP maximum segment lifetime (Time To Live) shall be set to 0xfe (decimal 254) if it is not configurable. When provision is made for configuration, the initial value should be the number currently in effect as published in Internet “Assigned Numbers.”6
•
Mobile stations shall handle TCP connection failures using the following procedure, unless disabled by the application interface:
3 4
7 8 9 10 11 12 13 14 15 16 17 18
(a) During initial connection synchronization, the number of retransmission attempts (R2) shall be 5 retransmissions, after which the connection should be closed.
19 20 21
(b) After the connection has been established, the default value of R2 shall be either 100 seconds or 10 retransmissions, after which the connection may be closed.7
22 23 24 25
•
The manufacturer shall provide a means for the application interface to disable this procedure. If this procedure is disabled, there shall be no maximum number of retransmission attempts during synchronization, and an established TCP connection shall remain open until explicitly closed by the mobile station or the IWF. The application interface shall be able to set the value of R2. R2 may be measured in time units or as a count of retransmissions.
•
IWFs shall follow either the procedure of 4.2.3.5 of RFC 1122, or the procedure above.
26 27 28 29 30 31 32
5This limit is intended to prevent excessive segment error rates under conditions where the RLP
frame error rate is high. The TCP MSS option provides a means for restricting the segment size to a smaller value if required by an implementation. 6The most recently published value is 64, per RFC 1700. 7It is recommended that the application keep the connection open, and wait for notification of an
improvement in connectivity or link quality before attempting further retransmissions.
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2.4
2
2.4.1
3
The network layer for CDMA analog fax services is based on the Internet network layer protocol known as the Internet Protocol (IP), as described in RFC 791.
4 5 6 7 8
Network Layer General Requirements
The network layer shall also include the Internet Control Message Protocol (ICMP), as described in RFC 792. The implementation shall comply with the requirements of RFC 791 as amended by RFC 1122, with the following modifications: •
The mobile station network layer is not required to support the subnet addressing modes described in RFC 950. The IWF network layer should support subnet addressing as described in RFC 950 and RFC 1122.
•
The mobile station network layer may assume that it is locally connected to the IWF.
•
Mobile stations shall not perform “Dead Gateway Detection” (see 3.3.1.4 of RFC 1122) nor “New Gateway Selection” (see 3.3.1.5 of RFC 1122) in the network layer.
16
•
The Address Mask Request and Reply are obsolete, and should not be sent.
17
•
The mobile station is not required to support the Internet Group Management Protocol (IGMP) as described in RFC 1112.
•
The network layer shall not fragment IP datagrams for transmission on the Um
9 10 11 12 13 14 15
18 19
21
interface. If fragmented datagrams that are received from a network cannot be transmitted on the Um interface after reassembly, they shall be discarded as
22
specified in RFC 1191.
20
23
•
24
The mobile station shall support the End of Option list IP option and the No Operation IP option (see RFC 791).
26
The interface between the network layer and the transport layer shall comply with the requirements of 3.4 of RFC 1122.
27
2.4.2
28
The IWF assigns the mobile station a temporary IP address upon call establishment. This IP address shall be valid and should be uniquely assigned to the mobile station for the duration of the call.8 The IWF transfers the temporary IP address to the mobile station using IPCP (see 2.5.3).
25
29 30 31
Assignment of Network Address
8The IP address should have a valid format as if it were assigned by IANA. However, for async data
and fax services, IP addresses need not be requested from IANA if the Internet is not used as part of the intersystem network.
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2.5
2
2.5.1
3
The Sub-Network Dependent Convergence Function (SNDCF) performs header compression on the headers of the transport and network layers. This function is negotiated using the PPP Internet Protocol Control Protocol (see 2.5.3).
4 5 6 7 8 9 10
Data Link Layer Sub-Network Dependent Convergence Function
Mobile stations shall support Van Jacobson TCP/IP header compression, as described in RFC 1144, “Compressing TCP/IP Headers for Low-Speed Serial Links.” A minimum of 1 compression slot shall be negotiated.9 The IWF shall support TCP/IP header compression compatible with that required for mobile stations. Negotiation of the parameters of header compression shall be carried out using IPCP, as specified in 2.5.2.
15
The SNDCF sublayer shall accept network layer datagrams from the network layer, perform header compression as required, and pass the datagram to the PPP layer, indicating the appropriate PPP protocol identifier. The SNDCF sublayer shall receive network layer datagrams with compressed or uncompressed headers from the PPP layer, decompress the datagram header as necessary, and pass the datagram to the network layer.
17
2.5.2
18
The data link layer uses PPP, as described in RFC 1661, “The Point-to-Point Protocol (PPP),” and RFC 1662, “PPP in HDLC Framing,” for datagram encapsulation and framing, respectively. The PPP Link Control Protocol (LCP) is used for initial link establishment, and to negotiate optional link capabilities.
11 12 13 14
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
PPP Layer
The data link layer uses “The PPP Internet Protocol Control Protocol (IPCP),” as described in RFC 1332, to negotiate IP addresses and TCP/IP header compression. The PPP layer shall accept header compressed network layer datagrams from the SNDCF, and shall encapsulate them in the PPP Information field. The packet shall be framed using the octet-synchronous framing protocol defined in RFC 1662, except that there shall be no inter-frame fill (see 4.1.1 of RFC 1662): No flag octets shall be sent between a flag octet that ends one PPP frame and the flag octet that begins the subsequent PPP frame. The framed PPP packets shall be passed to the RLP layer for transmission. The data link layer shall accept received octets from the RLP layer, and re-assemble the original PPP packets. The PPP process shall discard any PPP packet for which the received Frame Check Sequence (FCS), specified in 3.1 of RFC 1662, is not equal to the computed value.
9Implementation note: the code provided in RFC 1144 will not work with less than 3 compression
slots. Also, if the mobile station is to support additional data services, it should allocate additional slots. A minimum of 4 compression slots is recommended for such mobile stations.
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2.5.3
2
The IPCP sublayer shall support negotiation of the IP-address (type = 3) and IPCompression-Protocol (type = 2) parameters.
3
IPCP
7
IPCP shall negotiate a temporary IP address for the mobile station whenever a transport layer connection is actively opened. Mobile stations shall maintain the temporary IP address only while a transport layer connection is open or is being opened, and shall discard the temporary IP address when the transport layer connection is closed.
8
2.5.4
9
If the protocol identifier is 0xc021, the PPP layer shall process the packet according to the PPP Link Control Protocol (LCP). If the protocol identifier is 0x8021, the IPCP sublayer shall process the packet. For other supported protocol identifiers,10 the PPP layer shall remove the PPP encapsulation and shall pass the datagram and protocol identifier to the SNDCF. For unsupported protocol identifiers, the LCP Protocol-Reject shall be passed to the RLP layer for transmission.
4 5 6
10 11 12 13 14
Link Control Protocol
17
The mobile station shall support the PPP LCP Configure-Request, Configure-Ack, Configure-Nak, Configure-Reject, Terminate-Request, Terminate-Ack, Code-Reject, and Protocol-Reject. Other LCP packet types may also be supported.
18
The PPP LCP shall negotiate the following configuration options:
15 16
•
Async control character map. The mobile station shall not require any mapping of control characters. The IWF may negotiate mapping of control characters.
21
•
Protocol field compression (applied when the protocol number is less than 0xff).
22
•
Address and control field compression (applied when the protocol number is not 0xc021).
19 20
23 24 25 26 27
The mobile station may support other configuration options (such as maximum receive unit, authentication protocol, link quality protocol, or magic number). When an option is received which is not supported, the Configure-Reject shall be sent as an indication to the peer.
10The protocol identifiers required by this standard are 0x0021, 0x002d, 0x002f, 0xc021, and
0x8021.
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The mobile station and the BS/MSC shall support the physical layer, multiplex sublayer, radio link management, and call control as defined in [2], [3], [4], and [5].
3
REQUIREMENTS FOR THE RADIO INTERFACE
5
The mobile station and the BS/MSC shall not use quarter-rate frames to carry Service Option 20 or 21 data when Multiplex Option 1 is negotiated.
6
3.1
7
The mobile station and the BS/MSC shall use Service Option 20 when Multiplex Option 1 is the desired default multiplex option.
4
8
Service Option Number
10
When Multiplex Option 2 is desired as the default multiplex option, the mobile station and the BS/MSC shall use Service Option 21.
11
Mobile stations supporting Service Option 21 shall also support Service Option 20.
12
3.2
13
Service Option 20 shall support an interface with Multiplex Option 1 and may support an interface with Multiplex Option 2. RLP frames for Service Option 20 shall only be transported as primary traffic.
9
14 15
Multiplex Option Interface
18
Service Option 21 shall support an interface with Multiplex Option 2 and may support an interface with Multiplex Option 1. RLP frames for Service Options 21 shall only be transported as primary traffic.
19
3.3
20
3.3.1
21
The mobile station shall perform service negotiation compatible with the procedures described in[5], and the negotiated service configuration shall include only valid attributes for the negotiated service option as specified in Tables 3.3.1-1 and 3.3.1-2. Service option negotiation procedures are not supported for Service Options 20 and 21. The mobile station shall not accept a service configuration whose attributes are inconsistent with the valid service configuration attribute table for the service option. The default service configuration for the analog fax service option shall be as shown in the valid service configuration attribute table for the service option.
16 17
22 23 24 25 26 27 28
Procedures Using Service Negotiation Mobile Station Requirements
29 30
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Table 3.3.1-1. Valid Service Configuration Attributes for Service Option 20
1
Service Configuration Attribute
Valid Selections
Forward Multiplex Option
Multiplex Option 1 or 2
Reverse Multiplex Option
Multiplex Option 1 or 2
Forward Transmission Rates
Rate Set 1 with full rate, half rate and eighth rate frames enabled. Rate Set 2 with all rates enabled.
Reverse Transmission Rates
Rate Set 1 with full rate, half rate and eighth rate frames enabled. Rate Set 2 with all rates enabled.
Forward Traffic Type
Primary Traffic
Reverse Traffic Type
Primary Traffic
2 3
Table 3.3.1-2. Valid Service Configuration Attributes for Service Option 21
4
Service Configuration Attribute
Valid Selections
Forward Multiplex Option
Multiplex Option 1 or 2
Reverse Multiplex Option
Multiplex Option 1 or 2
Forward Transmission Rates
Rate Set 1 with full rate, half rate and eighth rate frames enabled. Rate Set 2 with all rates enabled.
Reverse Transmission Rates
Rate Set 1 with full rate, half rate and eighth rate rates frames enabled. Rate Set 2 with all rates enabled.
Forward Traffic Type
Primary Traffic
Reverse Traffic Type
Primary Traffic
5 6 7 8 9
If the mobile station accepts a service configuration, as specified in a Service Connect Message, that includes a service option connection using Service Options 20 or 21, the mobile station shall perform the following: •
If the mobile station is in the Conversation Substate, and the service option connection is not part of the previous service configuration the mobile station shall initialize and connect the service option at the action time associated with the Service Connect Message. The mobile station shall complete the initialization within 200 ms of starting the connection.
•
If the mobile station is not in the Conversation Substate, the mobile station shall initialize and connect the service option immediately upon entering the
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Conversation Substate and completing any further service negotiation. The mobile station shall complete the connection of the service option within 200 ms of starting the connection.
1 2 3 4 5 6 7
Commencing at the time when the service option is connected and continuing for as long as the service configuration includes the service option connection, the service option shall generate and transfer RLP frame data to the multiplex sublayer. The service option shall also transfer and process RLP frame data received from the multiplex sublayer.
12
When the transmitting side of the service option is connected, the service option shall generate and transfer RLP frame data to the multiplex sublayer. When the receiving side is connected, the service option shall transfer and process RLP frame data from the multiplex sublayer. See [5] for the actions to be taken when the transmitting side of a service option is not connected.
13
3.3.2
14
If the BS/MSC establishes a service configuration, as specified in a Service Connect Message, that includes a service option connection using Service Options 20 or 21, the BS/MSC shall connect the service option no later than the action time associated with the Service Connect Message.
8 9 10 11
15 16 17 18 19 20 21 22 23 24 25 26
BS/MSC Requirements
Commencing at the time when the service option is connected and continuing for as long as the service configuration includes the service option connection, the service option shall process received RLP data frames and generate and supply RLP data frames for transmission in accordance with this standard. When the transmitting side of the service option is connected, the service option shall generate and transfer RLP frame data to the multiplex sublayer. When the receiving side is connected, the service option shall transfer and process RLP frame data from the multiplex sublayer. See [5] for the actions to be taken when the transmitting side of a service option is not connected.
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3
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4
2
4.1
3
4.1.1
4
The mobile station shall initiate an analog fax connection by the following procedure:
5
When the TE2 goes off hook on the RJ-11 interface and requests initiation of an analog fax call, the MT2 shall issue an active OPEN call to the transport layer. The OPEN call shall specify the modem server port number (380) as destination port, with the source and destination IP addresses unspecified. The IP addresses shall be provided to the Network Layer after completion of IPCP configuration. Transport layer data shall not be sent on the Um interface prior to completion of IPCP configuration.
6 7 8 9 10
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
REQUIREMENTS FOR UM INTERFACE CALL PROCESSING Connection Establishment
The mobile station shall perform the Mobile Station Origination Operation requesting the appropriate analog fax service option number. The mobile station shall place the dial string in the Origination Message. The mobile station shall include as many characters of the dial string as possible without exceeding the message capsule size. The IWF should assign an IP address for the mobile station and issue a passive OPEN call with the foreign network address and port number unspecified to the transport layer. The OPEN call shall specify the modem server port number (380) as the local port, with the IWF’s IP address as the local address. Subsequent mobile station and BS/MSC call state transitions shall follow the requirements of [5]. When the mobile station and BS/MSC enter the Conversation Substate they may perform service negotiation (see [5]) to establish a service configuration including the requested data service option. Following connection of the requested service option, the mobile station, the BS/MSC and the IWF shall perform the actions specified in 4.1.4. When the analog fax service option becomes connected while in the Conversation Substate, the mobile station and the IWF shall perform the following actions: •
The mobile station application interface shall send the dial command (ATD) including the dial string preceded by the configuration command (AT+CFG).
•
Following reception of the ATD command, the IWF shall send CNG tone to the PSTN fax machine.
•
The IWF shall send the Max Rate Message to the mobile station after processing the ATD command.
•
If the IWF detects CED tone from the PSTN fax machine, the IWF shall send a Start CED Message to the mobile station.
•
If the mobile station is implemented as a MT2/TE2 pair, the MT2 shall send CED tone to the TE2 prior to sending the first V.21 message to the TE2.
•
The mobile station and the IWF shall follow the Mobile Transmitting Fax procedures (see 5.2 and 6.2).
29 30 31 32 33 34 35 36 37 38 39
Mobile Origination
4-1
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4.1.2
2
When a call is to be terminated to a mobile station directory number, the BS/MSC should determine the mobile station ID of the associated mobile station, and send a General Page Message to that mobile station. The General Page Message should include the appropriate Service Option number.11 Following connection of the requested service option, the mobile station the BS/MSC and the IWF shall perform the actions specified in 4.1.4. For analog fax calls, the IWF should assign an IP address for the mobile station and issue an active OPEN call to the transport layer. The OPEN call shall specify the modem client port number (379) as destination, with the IWF's IP address as the source address and the mobile station’s assigned IP address as the destination address.
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
The mobile station shall always respond to a General Page Message specifying an analog fax service option. Mobile stations may also be configurable to accept only analog fax service options. If so configured, a mobile station may respond to a General Page Message by including a request for these service options. After the mobile station enters the Waiting for Mobile Station Answer Substate the mobile station shall send a Connect Order after detecting an off-hook indication on the RJ-11 loop. The mobile station shall then enter the Conversation Substate. After the mobile station enters the Conversation Substate, the mobile station shall issue a passive OPEN call with the foreign network address and port number unspecified to the transport layer. The OPEN call shall specify the modem client port number (379) without a local network (IP) address. When the analog fax service option becomes connected while in the Conversation Substate, the mobile station and the IWF shall perform the following actions: •
The mobile station application interface shall send the answer command (ATA) preceded by the configuration command (AT+CFG).
•
The IWF shall send the Max Rate Message to the mobile station after processing the ATA command.
•
If the mobile station is implemented as an MT2/TE2 pair:
26 27 28 29
Mobile Termination
30
−
The MT2 shall immediately send CNG tone to the TE2 upon entering the Waiting for Mobile Station Answer Substate.
−
If the MT2 detects CED tone from the TE2, the MT2 shall send a Start CED Message to the IWF.
31 32 33 34 35
•
The IWF shall send CED tone to the PSTN fax machine prior to sending the first V.21 message to the PSTN fax machine.
11Methods for determining the service option number for mobile-terminated analog fax calls are
outside the scope of this standard. Approaches include a distinct directory number for analog fax service, two-stage dialing, and service option switching.
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•
2
The mobile station and the IWF shall follow the Mobile Receiving Fax procedures (see 5.1 and 6.1).
3
4.1.3
4
If the mobile station and BS/MSC are in the Conversation Substate with a connected service option other than analog fax, the mobile station or BS/MSC may initiate service negotiation procedures consistent with [5] to connect an analog fax service option.
5 6
Service Option Change to Analog Fax Service
13
The BS/MSC should open an L-Interface virtual circuit to the IWF prior to entering the Conversation Substate with a connected analog fax service option. Since the PSTN path for the call in progress has been previously established, the BS/MSC should establish the LInterface virtual circuit to the IWF as a mobile terminated call. If the BS/MSC initiated service negotiation to connect the analog fax service option, it should indicate the fax calling station and any requirement for T.30 Phase A signaling. The IWF should assign an IP address for the mobile station.
14
The IWF shall perform the following actions:
7 8 9 10 11 12
•
If the intial call was mobile terminated, the IWF shall issue an active OPEN call with the foreign network address and port number unspecified to the transport layer. The OPEN call shall specify the modem client port number (379) as the destination, with the IWF's IP address as the source address and the mobile station’s assigned IP address as the destination address.
•
If the inital call was mobile originated, the IWF shall issue a passive OPEN call with the foreign network address and port number unspecified to the transport layer. The OPEN call shall specify the client server port number (380) as the local port, with the IWF’s IP address as the source address.
•
After processing the AT+CFG and AT+CVF or AT+CVFQ? commands, the IWF shall send the Max Rate Message to the mobile station.
•
27
If the IWF determines that T.30 Phase A signaling is required, the IWF shall perform the following actions:
28
−
If the PSTN fax machine is the fax calling station, the IWF shall send CED tone to the PSTN fax machine prior to sending the first V.21 message to the PSTN fax machine.
−
If the mobile station is the fax calling station, the IWF shall immediately begin sending CNG tone to the PSTN fax machine. If the IWF detects CED tone from the PSTN fax machine, the IWF should send a Start CED Message to the mobile station.
15 16 17 18 19 20 21 22 23 24 25 26
29 30 31 32 33 34 35
•
If the PSTN fax machine is the fax calling station, the IWF shall follow the Mobile Receiving Fax procedures (see 6.1).
•
If the mobile station is the fax calling station, the IWF shall follow the Mobile Transmitting Fax procedures (see 6.2).
36 37 38 39 40
When the analog fax service option becomes connected while in the Conversation Substate, following service negotiation, the mobile station shall perform the following actions:
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•
The mobile station shall perform the actions specified in 4.1.4.
2
•
If the initial call was mobile terminated, the mobile station application interface shall issue a passive OPEN call with the foreign network address and port number unspecified to the transport layer. The OPEN call shall specify the modem client port number (379) without a local network (IP) address.
•
If the initial call was mobile originated, the mobile station application interface shall issue an active OPEN call to the transport layer. The OPEN call shall specify the modem server port number (380) as destination port, with the source and the destination IP addresses unspecified.
•
If service negotiation was initiated by the BS/MSC to connect the analog fax service option, the mobile station shall send the AT+CVFQ? command to query the IWF for determination of the fax calling station and any requirements for T.30 Phase A signaling. The AT+CVFQ? command shall be preceded by the configuration command (AT+CFG).
•
If service negotiation was initiated by the mobile station to connect the analog fax service option, the mobile station application interface shall send the AT+CVF command indicating the fax calling station and any requirement for T.30 Phase A signaling preceded by the configuration command (AT+CFG).
•
If the PSTN fax machine is the fax calling station, the mobile station is implemented as a MT2/TE2 pair, and the MT2 determines that T.30 Phase A signaling is required, the MT2 shall immediately begin sending CNG tone to the TE2. If the MT2 detects CED tone from the TE2, the MT2 should send a Start CED Message to the IWF. The mobile station (MT0 or MT2/TE2) shall follow the Mobile Receiving Fax procedures (see 5.1).
•
If the mobile station is the fax calling station implemented as a MT2/TE2 pair, and the MT2 determines that T.30 phase A signaling is required, the MT2 shall send CED tone to the TE2 prior to sending the first V.21 message to the TE2. The mobile station (MT0 or MT2/TE2) shall follow the Mobile Transmitting Fax procedures (see 5.2).
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
4.1.4
31
When either the mobile station or the BS/MSC enters the Conversation Substate with an analog fax service option connected, it shall begin RLP initialization/reset as described in [7]. The BS/MSC should also open an L-Interface virtual circuit to the IWF prior to the completion of RLP initialization. When the L-Interface virtual circuit has been opened, the IWF relay layer should signal this event to the PPP layer. The PPP layer and IPCP sublayer in the IWF shall then carry out self-configuration, as described in 2.5.3 and 2.5.4.
32 33 34 35 36 37 38 39 40 41
Conversation Substate
The IWF shall send an IPCP Configure-Request with an IP-Compression-Protocol parameter set consistent with 2.5.1 and with the IP-address parameter set to the IP address associated with the assigned IWF. The mobile station shall store the IWF's IP address and shall place the IWF's IP address in the destination address field of all IP datagrams sent while the transport layer remains connected.
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If the mobile station’s IPCP Configure-Request contains an IP address of all zeros, the IWF shall select an IP address to be used by the mobile station and shall send a Configure-Nak with the IP-address parameter set to the IP address selected. The IWF shall select an IP address for each mobile station using analog fax service options conforming with the requirements of 2.4.2. The mobile station’s IPCP sublayer shall store the assigned address and pass it to the network layer for use as a source address in all IP datagrams sent to the IWF while the transport layer connection remains open. The remaining exchange of IPCP configuration related messages shall be in accordance with RFC 1661.
10
When the transport layer enters the ESTABLISHED state, the transport layer may begin sending and receiving data to/from the peer application interface.
11
4.1.5
12
Soft handoff (see 6.6.6.2.7 of TIA/EIA/IS-95-A) or a CDMA-to-CDMA hard handoff (see 6.6.6.2.8 of TIA/EIA/IS-95-A) entailing only a change in the frame offset field shall not affect the state of any of the protocols for analog fax.
9
13 14 15 16 17 18 19 20
Traffic Channel Handoff
Following a CDMA-to-CDMA hard handoff (see 6.6.6.2.8 of TIA/EIA/IS-95-A) involving transitions between disjoint sets of BS/MSCs or a frequency change, the RLP layer shall be reset and immediately re-established. This is necessary to ensure proper re-establishment of RLP after an intersystem handoff, which is not distinguishable from other hard handoffs under TIA/EIA/IS-95-A. Data lost during the reset of RLP will be retransmitted by the transport layer.
23
CDMA-to-analog handoffs are not supported for Service Options 20 and 21. The mobile station and the IWF shall close the transport layer connection if the mobile station moves outside of CDMA coverage (see 3.9.2).
24
4.2
25
The analog fax service is considered connected when the transport layer is in the ESTABLISHED state.
21 22
26 27 28
Connection Release
Each of the following conditions shall cause the transport layer connection to be closed by means of the CLOSE call to the transport layer: •
The IWF detects that the PSTN connection has been lost or that the PSTN fax machine has released the connection.
•
The MT2 detects that the RJ-11 connection has been lost or that the TE2 has released the connection.
33
•
No messages have been exchanged over the Um interface for more than T12.
34
•
The mobile station moves away from CDMA coverage.
29 30 31 32
35 36 37 38 39
If the IWF detects a transport layer failure, as specified in 2.3, the IWF shall close the transport layer by means of an ABORT call. If the IWF closes the transport layer in this manner, the IWF should release the L-Interface virtual circuit. If the IWF closes the L-Interface virtual circuit, the BS/MSC should release the traffic channel to the Mobile Station, and should release the PSTN call.
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The BS/MSC should close the L-Interface virtual circuit, and release the PSTN call when any of the following occur:
3
•
The BS/MSC receives a Release Order with a power-down indication.
4
•
The BS/MSC cannot support the requested service option.
5
•
The mobile station releases the traffic channel.
6
•
A Lock Order is sent to the mobile station.
7 8
The mobile station shall close the transport layer by means of an ABORT call to the transport layer if any of the following occur:
9
•
The mobile station powers down.
10
•
The mobile station receives a Release Order indicating that the requested service option is rejected.
•
A Lock Order is received by the mobile station.
11 12 13 14
When the transport layer is to be closed via a CLOSE call to the transport layer and a traffic channel is active, the mobile station or BS/MSC shall perform the following:
15
•
If the connection is to be closed because the mobile station is powering down, the mobile station may send a Release Order with power-down indication and immediately power down.
•
In all other cases, the transport layer initiating the close shall close the connection in accordance with the requirements of RFC 793.
16 17 18 19 20
4.3
21
Authentication of mobile station initiated analog fax calls shall be conducted according to the procedure described in 6.3.12 of TIA/EIA/IS-95-A. For mobile-originated data calls, the BS/MSC should complete an authentication Unique Challenge immediately after assigning the traffic channel, and before connecting the analog fax service option.
22 23 24
Authentication
25
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5
2
In all the states of this section, the following procedures shall take precedence over the specific procedures in the current state:
3 4
MOBILE PROCEDURES
•
The MT2 shall continuously monitor both the TE2 and the Um interface for messages.
•
If there are no messages exchanged over the Um interface for more than T12, the MT2 shall close the transport layer and direct the analog interface to release the call.
•
The MT2 shall use the format specified in section 7 for messages exchanged over the Um interface.
•
If the MT2 receives an on-hook signal from the TE2, the MT2 shall close the transport layer.
•
If the MT2 detects that the transport layer has been closed, the MT2 shall signal the analog interface to release the call.
•
If the MT2 detects V.21 preamble from the TE2, the MT2 shall continuously monitor the analog interface and not send any response to the TE2 until the V.21 carrier has dropped.
•
If the MT2 receives a DCN from the TE2, the MT2 shall send the DCN to the IWF and shall direct the analog interface to release the call.
•
If the MT2 receives a DCN over the Um interface, the MT2 shall send the DCN to the
5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
TE2 and wait for the TE2 to go on hook. If the MT2 does not receive an on-hook signal within T11, the MT2 shall close the transport layer and direct the analog interface to release the call.
21 22 23
•
If the MT2 receives a CRP from the TE2, the MT2 shall wait for a period of T1 and then resend the previous message to the TE2. The MT2 shall not send CRP over the Um interface.
•
29
If the MT2 sends an NSF, CSI, DIS, NSC, CIG, DTC, TSI, DCS-TCF, EOP, MPS, EOM, or PRI-XXX message to the TE2, the MT2 shall process the response from the TE2 as follows:
30
−
If no response is received within T10, the MT2 shall repeat the previous message to the TE2 in its entirety (i.e. optional frames included) and remain in the same state.
−
If the response is invalid (e.g. it fails the FCS or contains an incomplete frame), the MT2 shall wait for a period of T1, repeat the previous message to the TE2 in its entirety (i.e. optional frames included), and remain in the same state.
24 25 26
27 28
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1 2 3
•
4 5 6 7
•
If the MT2 receives a non-final frame message as defined in 5.3.5 of T.30 over the Um interface, the MT2 shall store the message.
•
If the MT2 receives a final frame message as defined in 5.3.5 of T.30 over the Um interface and the MT2 is currently not transmitting preamble as a result of receiving a previous Preamble Message (see 7.2.3), the MT2 shall send V.21 preamble to the TE2 for a period of T5.
10 11 12 13
•
If the MT2 receives a Preamble Message (see 7.2.3) over the Um interface, the MT2 shall immediately send V.21 preamble to the TE2 for a period of at least T5. The MT2 shall continue to send preamble until it has received a final frame message over the Um interface.
•
If the MT2 receives a Data Message (see 7.2.2) over the Um interface, the MT2 shall
14 15 16 17
not transmit V.21 preamble to the TE2.
18 19
•
If the MT2 receives a duplicate message13 from the TE2, the message shall be discarded. If the duplicate message is received after the MT2 has sent a response to the original message, the MT2 shall resend the previous response to the TE214.
•
If the MT2 receives a message from either the TE2 or the Um interface that is not expected to be received in the current state, the MT2 shall discard the message and remain in the current state.
•
If the MT2 modifies a message with an FCS, the MT2 shall recompute the FCS.
20 21 22 23 24 25
Whenever the MT2 sends a message to the TE2, the MT2 shall avoid a message collision12 on the analog interface.
In all the states of this section, the following procedures shall apply unless specified otherwise in the current state:
8 9
If the response is valid, the MT2 shall follow the procedures specified in the current state.
12 To avoid message collisions, the MT2 shall use the collision timer, T (see 9). 7 13 A duplicate message is a message that is transmitted by a fax machine more than once in
anticipation of a response from the remote fax machine. According to T.30, fax machines will repeat some messages if an appropriate response is not received within a specified amount of time. 14 For example, in response to a DCS from the TE2, the MT2 sends a CFR response. If the MT2
receives a duplicate DCS message, the MT2 shall resend the CFR response.
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5.1
Mobile Receiving Fax
Wait for Local DIS Substate MCF, RTP, or RTN
DIS
Wait for Remote DCS Substate
DCS FTT Wait for Local CFR/FTT Substate
CFR
RTP or RTN
Image Transfer State MCF End of image
Post Image Transfer State MPS
EOM EOP
MPS Substate RTN
EOP Substate RTP or MCF
EOM Substate
NOTE: not all transitions and states are shown
End call
2
Figure 5.1-1. MT2 RX Fax Layer States in a Mobile Receiving Fax Call
3 4
5.1.1
5
5.1.1.1 Wait for Local DIS Substate
6
The MT2 shall process the messages from the TE2 as follows:
7 8 9
•
Mobile Connecting State
If the message is an NSF or NSC, the MT2 shall examine the capabilities advertised in the message. If the MT2 cannot support any of the options in the message, the MT2 shall either discard the message or modify the contents to inhibit such
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options. If not discarded, the MT2 shall store this message. The MT2 shall remain in this substate.
1 2 3
•
If the message is a CSI, DIS, CIG, or DTC, the MT2 shall store the message and remain in this substate.
•
If any of the above messages is a final frame message and all the stored messages were received correctly, the MT2 shall forward all the stored messages to the IWF in the order that they were received from the TE2 and enter the Wait For Remote DCS Substate of the Mobile Connecting State.
4 5 6 7 8 9 10
11
5.1.1.2 Wait for Remote DCS Substate The MT2 shall process messages received over the Um interface as follows: •
If the message is a TSI, CIG, or CSI, the MT2 shall store the message and remain in this substate.
•
If the message is a DCS, the MT2 shall enter the Wait for Local CFR/FTT Substate of the Mobile Connecting State.
•
If the message is an NSC or NSF, the MT2 shall examine the capabilities advertised in the message. If the MT2 cannot support any of the options in the message, the MT2 shall either discard the message or modify the contents to inhibit such options. If not discarded, the MT2 shall store the message. The MT2 shall remain in this substate.
•
If the message is a DTC or DIS, the MT2 shall modify the bits of the message in accordance with section 10. The MT2 shall then send NSC or NSF (if any stored), CIG or CSI (if any stored), and DTC or DIS to the TE2 in the order the messages were received from the IWF. Upon receiving a response from the TE2, the MT2 shall enter the Wait For Local DCS Substate of the Mobile Connecting State under the Mobile Procedures of a Mobile Transmitting Fax Call (see 5.2.1.2).
•
If the message is an NSS, the procedures to be followed are left up to the MT2 manufacturer.
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
5.1.1.3 Wait for Local CFR/FTT Substate
29
If this substate is entered from the Wait for Remote DCS Substate, the MT2 shall perform the following procedures on the DCS received from the IWF:
30
•
Set the rate bits 11, 12, 13, and 14 to ‘1000’ if the rate bits 11, 12, 13, and 14 of the DIS/DTC advertised by the TE2 were ‘1000’ (i.e. the TE2 is only capable of V.29 modulation).
34
•
Set the MSLT bits 21, 22, and 23 in accordance with Table 5.1.1.3-1.
35
•
Store a copy of the modified DCS.
36
•
Send the stored TSI (if any) and the modified DCS to the TE2.
31 32 33
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Table 5.1.1.3-1. MSLT Resetting in the DCS
1
2 3 4 5 6 7 8
MSLT bits advertised by the TE2
New MSLT bits if DCS bit 15 = 0
New MSLT bits if DCS bit 15 = 1
000
000
000
001
001
001
010
010
010
100
100
100
011
010
100
110
000
010
101
001
000
111
111
111
If this substate is entered from either the MPS Substate or the EOP Substate of the Post Image Transfer State, the MT2 shall send the last stored TSI (if any) and the last stored DCS to the TE2. After sending a DCS to the TE2, the MT2 shall wait for T2 and then generate and send TCF to the TE2 at the modulation rate specified in the DCS. The MT2 shall then process messages from the TE2 as follows: •
9 10 11 12 13
If the message is an FTT, the MT2 shall forward the message to the IWF. The MT2 shall then set the modulation rate in the DCS (bits 11, 12, 13, 14) to the next lower rate, store a copy of the DCS, and send the stored TSI (if any) and the DCS followed by a TCF to the TE2. The TCF shall be sent by the MT2 at the modulation rate specified in the DCS after maintaining silence for a period of T2 after the DCS is sent. The MT2 shall remain in this substate.
14
If an FTT is received again, the MT2 shall repeat this process until a CFR is received, or until 6 attempts have been made at the lowest supported modulation rate15. If an FTT is received after 6 attempts at the lowest supported modulation rate, the MT2 shall send DCN to the TE2 and the IWF. The MT2 shall direct the analog interface to release the call.
15 16 17 18 19 20
•
21
If the message is a CFR, the MT2 shall enable page start timer, T6, and send the CFR to the IWF. The MT2 shall enter the Image Transfer State.
22
5.1.2
Image Transfer State
23
The MT2 shall process messages from the IWF as follows:
15 The lowest rate is determined from the DIS or DTC received from the TE2.
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The MT2 shall monitor for a Data Message in order to detect the incoming image data.
3
−
If page start timer (T6) expires, the MT2 shall generate and send blank scan lines (see ITU-T T.4 4.1) in T3 intervals to the TE2 until image data is received from the IWF. The MT2 should maintain a count of inserted blank scan lines and use this to maintain a fixed number of lines16 in the page.
−
If the image data is received before page start timer expires, the MT2 shall send the image data to the TE2.
1
4 5 6 7 8 9
•
The MT2 shall not transmit the address, control, and flag fields of the received Data Message over the RJ-11 interface.
•
The MT2 shall transmit image data to the TE2 at the last modulation rate accepted by the TE2. The image scan lines shall be sent at intervals that meet the TE2 MSLT requirement.
•
If the MT2 does not have image data to send to the TE2, the MT2 shall insert fill bits. When fill bits are inserted, the duration of each image scan line shall not exceed T3.
•
The MT2 shall monitor the received HDLC information for an HDLC flag which indicates the end of the image data. Upon detecting the end of image data, the MT2 shall drop the high rate carrier to the TE2 then remain silent on the RJ-11 interface for a period of at least T4. The MT2 shall then enter the Post Image Transfer State.
•
If the MT2 receives a DCN over the Um interface, the MT2 shall stop transmitting
10 11 12 13 14 15 16 17 18 19 20
22
any image data to the TE2 and send V.21 preamble before forwarding the message to the TE2.
23 24 25
5.1.3
Post Image Transfer State
26
The MT2 shall process messages from the IWF as follows:
27
•
If the message is an EOP, the MT2 shall enter the EOP Substate.
28
•
If the message is an MPS, the MT2 shall enter the MPS Substate.
29
•
If the message is an EOM, the MT2 shall enter the EOM Substate.
30
•
If the message is a procedure interrupt (PRI-XXX), the MT2 shall discard the message and send a DCN to the TE2. The MT2 shall also send a DCN to the IWF and direct the analog interface to release the call.
31 32
16 There is space for a fixed number of lines in a standard size page (i.e. fixed page size). The MT2
should extract the vertical resolution and page size parameters from the stored DCS and compute the number of lines allowed. If the receiving fax machine uses an unlimited page size (such as a thermal paper roll), it may not be necessary to delete any lines from the page.
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In all the substates below (5.1.3.1, 5.1.3.2, and 5.1.3.3), if the message received from the TE2 is a PIN or PIP, the MT2 shall forward the message to the IWF and remain in the same substate.
4
5.1.3.1 EOP Substate
5
Upon entry to this substate, the MT2 shall send the EOP to the TE2. The MT2 shall then process messages from the TE2 as follows:
1 2
6 7
•
If the message is an MCF or RTP, the MT2 shall send the message to the IWF and wait for a period of T1. The MT2 shall then send a DCN to the TE2 and direct the analog interface to release the call.
•
If the message is an RTN, the MT2 shall send the message to the IWF and enter the Wait For Local CFR/FTT Substate of the Mobile Connecting State.
8 9 10 11 12
5.1.3.2 MPS Substate
13
Upon entry to this substate, the MT2 shall send the MPS to the TE2. The MT2 shall then process messages from the TE2 as follows:
14 15
•
If the message is an MCF, the MT2 shall enable page start timer (T6, see 9), send the MCF to the IWF, and enter the Image Transfer State.
•
If the message is an RTP or RTN, the MT2 shall forward the message to the IWF and enter the Wait For Local CFR/FTT Substate of the Mobile Connecting State.
16 17 18 19
5.1.3.3 EOM Substate
20
Upon entry to this substate, the MT2 shall send the EOM to the TE2 and wait for a response. If the message from the TE2 is an MCF, RTP or RTN, the MT2 shall send the message to the IWF and enter the Wait For Local DIS Substate of the Mobile Connecting State.
21 22 23
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5.2
Mobile Transmitting Fax
W ait for Remotel DIS Substate MCF, RTP, or RTN
DIS
W ait for Local DCS Substate
DCS
FTT
Training Substate RTN RTP or RTN
CFR
Image Transfer State MCF End of image
Post Image Transfer State MPS
EOM EOP
MPS Substate
EOP Substate RTP or MCF
EOM Substate
NOTE: not all transitions and states are shown
Disconnect Substate 2 3
Figure 5.2-1. MT2 TX Fax Layer States in a Mobile Transmitting Fax Call
4 5
5.2.1
6
5.2.1.1 Wait For Remote DIS Substate
7
The MT2 shall process messages from the IWF as follows:
8 9
•
Mobile Connecting State
If the message is a Start CED Message (see 7.2.5), the MT2 shall send CED tone to the TE2 except when the MT2 enters this substate at the beginning of a call where
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CED tone was already sent during call set-up. After CED has been sent, the MT2 shall remain silent for T9 before transmitting further signals to the TE2. The MT2 shall remain in this substate.
1 2 3 4
•
If the message is a Control Message (see 7.2.1) and it is the first Control Message since the beginning of the fax call, the MT2 shall send CED tone to the TE2 if Phase A tones are required and CED tone has not already been sent. After CED has been sent, the MT2 shall remain silent for T9 before transmitting further signals to the TE2. The MT2 shall process the Control Message as specified below.
•
If the message is an NSF, the MT2 shall examine the capabilities advertised in the message. If the MT2 cannot support any of the options in the message, the MT2 shall either discard the message or modify the contents to inhibit such options. If not discarded, the MT2 shall store the message. The MT2 shall remain in this substate.
•
If the message is a CSI, the MT2 shall store the message and remain in this substate.
•
If the message is a DIS, the MT2 shall modify the bits of the message in accordance with section 10, store the message, and remain in this substate.
•
If any of the above messages is a final frame message the MT2 shall send all stored messages to the TE2 in the order that they were received from the IWF. Upon receiving a response from the TE2, the MT2 shall enter the Wait For Local DCS Substate of the Mobile Connecting State.
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
5.2.1.2 Wait For Local DCS Substate
23
If the MT2 enters this substate from any substate other than the Training Substate, the MT2 shall clear transmitter trained flag (see 5.2.4.1) and receiver trained flag (see 5.2.4.2).
24
26
If a message from the IWF arrives at the MT2 when either the MT2 is servicing a response from the TE2 or collision timer has expired, the MT2 shall store the message.
27
The MT2 shall process messages from the TE2 as follows:
25
•
If the message is a TSI, and it is the first TSI received by the MT2 since receiving a DIS or DTC from the IWF, the MT2 shall forward this message to the IWF and remain in this substate. If the message is a TSI but not the first TSI, the MT2 shall discard the message and remain in this substate.
•
34
If the message is a DCS, and it is the first DCS received by the MT2 since receiving a DIS or DTC from the IWF, the MT2 shall perform the following in the order specified:
35
−
Store a copy of the DCS.
36
−
Send the DCS to the IWF.
37
−
Set receiver rate (see 5.2.5.1) equal to the rate specified in the DCS.
38
−
Clear receiver trained flag and transmitter trained flag.
39
−
Set transmitter rate (see 5.2.5.2) to the rate specified in the DCS.
28 29 30 31 32 33
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C.S0017-007-A v1.0
1
−
Wait for TCF from the TE2. If the training attempt is successful, the MT2 shall set transmitter trained flag.
−
Enter the Training Substate of the Mobile Connecting State.
2 3
•
6
If the message is a DCS, and it is not the first DCS received by the MT2 since receiving a DIS or DTC from the IWF, the MT2 shall perform the following in the order specified:
7
−
Set transmitter rate to the rate specified in the DCS.
8
−
Wait for TCF from the TE2. If the training attempt is successful, the MT2 shall set transmitter trained flag.
−
Enter the Training Substate of the Mobile Connecting State.
4 5
9 10 11
•
If the message is an NSC, NSF, CIG, CSI, DTC, or DIS, the MT2 shall enter the Wait for Local DIS Substate of the Mobile Connecting State under the Mobile Procedures of a Mobile Receiving Fax Call (see 5.1.1.1).
•
If the message is an NSS, the procedures to be followed are left up to the MT2 manufacturer.
12 13 14 15 16
5.2.1.3 Training Substate
17 18
If a message from the IWF arrives at the MT2 when either the MT2 is servicing a response from the TE2 or collision timer has expired, the MT2 shall store the message.
19
The MT2 shall execute the following procedures in the order specified:
20
•
The MT2 shall process all stored messages from the IWF as follows:
21
−
If the message is a CFR, the MT2 shall set receiver trained flag.
22
−
If the message is an FTT, the MT2 shall check receiver rate. If receiver rate is above the lowest possible modulation rate17, the MT2 shall decrement receiver rate to the next lower rate. If receiver rate is at the lowest possible modulation rate, the MT2 shall not modify receiver rate.
23 24 25
•
28
The MT2 shall compare the modulation rate of the TE218 with receiver rate. If any of the following conditions are met, the MT2 shall send an FTT to the TE2 and enter the Wait for Local DCS Substate of the Mobile Connecting State.
29
−
The TE2 modulation rate is greater than the PSTN fax machine modulation rate (transmitter rate > receiver rate).
−
The TE2 modulation rate is greater than the rate specified in the Max Rate Message.
−
The transmitter is not trained (Transmitter Trained Flag is not set).
26 27
30 31 32 33
17 The lowest rate is determined from the DIS or DTC received from the IWF. 18 The MT2 shall determine the modulation rate of the TE2 from the most recently received DCS.
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C.S0017-007-A v1.0
1
•
2
If none of the above conditions are met, the MT2 shall check receiver trained flag. −
If receiver trained flag is set, the MT2 shall send a CFR to the TE2 and enter the Image Transfer State.
−
If receiver trained flag is not set and if three consecutive DCS-TCF messages from the TE2 are unanswered, the MT2 shall send an FTT to the TE2 and enter the Wait For Local DCS Substate of the Mobile Connecting State.
−
If receiver trained flag is not set and if the number of unanswered DCS-TCF messages from the TE2 is less than three, the MT2 shall enter the Wait For Local DCS Substate of the Mobile Connecting State.
3 4 5 6 7 8 9 10
5.2.2
Image Transfer State
11
The MT2 shall process image data from the TE2 as follows: •
Receive image data at the rate specified in the last DCS message from the TE2 (transmitter rate).
14
•
Send image data to the IWF in a Data Message (see 7.2.2).
15
•
Strip fill bits from the image data before forwarding the data to the IWF.
16
•
18
Terminate the Data Message with an HDLC flag and enter the Post Image Transfer State upon detecting the end of image data from the TE2. The end of image data shall occur when any of the following is detected by the MT2:
19
−
RTC.
20
−
Drop of high rate carrier.
21
−
V.21 preamble (belonging to the proceeding EOP, MPS, or EOM message or their corresponding PRI versions).
12 13
17
22 23
5.2.3
24
27
Upon entry into this state, the MT2 shall wait for post-page messages from the TE2. If the MT2 detects a preamble on the RJ-11 interface for T8 continuously and the MT2 has not sent a Preamble Message to the IWF since entering this state, the MT2 shall send a Preamble Message over the Um interface. Upon receiving the rest of the message from the
28
TE2, the MT2 shall transmit the message to the IWF.
29
The MT2 shall process the message from the TE2 as follows:
25 26
Post Image Transfer State
30
•
If the message is an EOP, the MT2 shall enter the EOP Substate.
31
•
If the message is an MPS, the MT2 shall enter the MPS Substate.
32
•
If the message is an EOM, the MT2 shall enter the EOM Substate.
33
•
If the message is a procedure interrupt (PRI-XXX), the MT2 shall send the message to the IWF and remain in the Post Image Transfer State.
34 35 36 37
In the following substates of the Post Image Transfer State, the MT2 shall monitor the TE2 for repeated post-page messages. If the MT2 receives a total of three (3) post-page messages from the TE2, the MT2 shall start timer T13. Upon expiration of T13, the MT2
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C.S0017-007-A v1.0
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shall start sending V.21 preamble to the TE2 if a response has not been sent. The MT2 shall continue to send the V.21 preamble until it has a response to send to the TE2.
5
In the following substates of the Post Image Transfer State, if the message received from the IWF is a PIN or PIP, the MT2 shall send a DCN to the TE2. The MT2 shall also send a DCN to the IWF and direct the analog interface to release the call.
6
5.2.3.1 EOP Substate
7
The MT2 shall process messages from the IWF as follows:
3 4
8
•
If the message is an MCF or RTP, the MT2 shall send the message to the TE2 and enter the Disconnect Substate.
•
If the message is an RTN, the MT2 shall send the message to the TE2 and enter the Wait For Local DCS Substate of the Mobile Connecting State.
9 10 11 12
5.2.3.2 MPS Substate
13
The MT2 shall process messages from the IWF as follows:
14
•
If the message is an MCF, the MT2 shall send the message to the TE2 and enter the Image Transfer State.
•
If the message is an RTP or RTN, the MT2 shall send the message to the TE2 and enter the Wait For Local DCS Substate of the Mobile Connecting State.
15 16 17 18
5.2.3.3 EOM Substate
19
21
The MT2 shall wait for a message from the IWF. If the message is an MCF, RTP, or RTN, the MT2 shall send the message to the TE2 and enter the Wait for Remote DIS Substate of the Mobile Connecting State.
22
5.2.3.4 Disconnect Substate
23
If the MT2 receives a DCN from the TE2, the MT2 shall discard the DCN, close the transport layer, and direct the analog interface to release the call.
20
24
26
If the MT2 does not receive a DCN from the TE2 within T11, the MT2 shall close the transport layer and direct the analog interface to release the call.
27
5.2.4
28
5.2.4.1 Transmitter Trained Flag
29
This flag is set by the MT2 when the MT2 receives a valid TCF from the TE2.
30
5.2.4.2 Receiver Trained Flag
31
This flag is set by the MT2 when the MT2 receives a CFR from the IWF.
32
5.2.5
33
5.2.5.1 Receiver Rate
34
The current modulation rate being negotiated between the IWF and the PSTN fax machine.
35
5.2.5.2 Transmitter Rate
36
The current modulation rate being negotiated between the MT2 and the TE2.
25
Flags
Rates
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No text.
3
5-13
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6
2
In all the states of this section, the following procedures shall take precedence over the specific procedures in the current state:
3
IWF PROCEDURES
•
The IWF shall continuously monitor both the PSTN fax machine and the Um interface for messages.
•
If there are no messages exchanged over the Um interface for more than T12, the IWF shall close the transport layer and direct the analog interface to release the call.
•
The IWF shall use the format specified in section 7 for messages exchanged over the Um interface.
•
If the IWF receives an on-hook signal from the PSTN fax machine, the IWF shall close the transport layer.
•
If the IWF detects that the transport layer has been closed, the IWF shall signal the analog interface to release the call.
•
If the IWF detects V.21 preamble from the PSTN fax machine, the IWF shall continuously monitor the analog interface and not send any response to the PSTN fax machine until the V.21 carrier has dropped.
•
If the IWF receives a DCN from the PSTN fax machine, the IWF shall send the DCN to the MT2 and shall direct the analog interface to release the call.
•
If the IWF receives a DCN over the Um interface, the IWF shall send the DCN to the PSTN fax machine and wait for the PSTN fax machine to go on hook. If the IWF does not receive an on-hook signal within T11, the IWF shall close the transport layer and direct the analog interface to release the call.
•
If the IWF receives a CRP from the PSTN fax machine, the IWF shall wait for a period of T1 and then resend the previous message to the PSTN fax machine. The IWF shall not send CRP over the Um interface.
•
28
If the IWF sends an NSF, CSI, DIS, NSC, CIG, DTC, TSI, DCS-TCF, EOP, MPS, EOM, or PRI-XXX message to the PSTN fax machine, the IWF shall process the response from the PSTN fax machine as follows:
29
−
If no response is received within T10, the IWF shall repeat the previous message to the PSTN fax machine in its entirety (i.e. optional frames included) and remain in the same state.
−
If the response is invalid (e.g. it fails the FCS or contains an incomplete frame), the IWF shall wait for a period of T1, repeat the previous message to the PSTN fax machine in its entirety (i.e. optional frames included), and remain in the same state.
4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
26 27
30 31 32 33 34 35
6-1
C.S0017-007-A v1.0 −
1 2 3
•
Whenever the IWF sends a message to the PSTN fax machine, the IWF shall avoid a message collision19 on the analog interface.
•
If the IWF is in a tandem call and it receives a message from the PSTN to which it should respond with a V.21 message, the IWF shall immediately begin sending V.21 preamble to the PSTN. The IWF shall continue to send V.21 preamble until it has a message to forward or the IWF determines that the call must be dropped.
4 5 6 7 8 9 10 11
In all the states of this section, the following procedures shall apply unless specified otherwise in the current state: •
If the IWF receives a non-final frame message as defined in 5.3.5 of T.30 over the Um interface, the IWF shall store the message.
•
If the IWF receives a final frame message as defined in 5.3.5 of T.30 over the Um interface and the IWF is currently not transmitting preamble as a result of receiving a previous Preamble Message (see 7.2.3), the IWF shall send V.21 preamble to the PSTN fax machine for a period of T5.
•
If the IWF receives a Preamble Message (see 7.2.3) over the Um interface, the IWF
12 13 14 15 16 17
shall immediately send V.21 preamble to the PSTN fax machine for a period of at least T5. The IWF shall continue to send preamble until it has received a final frame message over the Um interface.
18 19 20 21
•
If the IWF receives a Data Message (see 7.2.2) over the Um interface, the IWF shall not transmit V.21 preamble to the PSTN fax machine.
•
If the IWF receives a duplicate message20 from the PSTN fax machine, the message shall be discarded. If the duplicate message is received after the IWF has sent a response to the original message, the IWF shall resend the previous response to the PSTN fax machine21.
•
If the IWF receives a message from either the PSTN fax machine or the Um interface that is not expected to be received in the current state, the IWF shall discard the message and remain in the current state.
•
If the IWF modifies a message with an FCS, the IWF shall recompute the FCS.
22 23 24 25 26 27 28 29 30
If the response is valid, the IWF shall follow the procedures specified in the current state.
19 To avoid message collisions, the IWF shall use the collision timer, T (see 9). 7 20 A duplicate message is a message that is transmitted by a fax machine more than once in
anticipation of a response from the remote fax machine. According to T.30, fax machines will repeat some messages if an appropriate response is not received within a specified amount of time. 21 For example, in response to an MPS from the PSTN fax machine, the IWF sends an MCF
response. If the IWF receives a duplicate MPS message, the IWF shall resend the MCF response.
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C.S0017-007-A v1.0
1
6.1
Mobile Receiving Fax
W ait for Remotel DIS Substate MCF, RTP, or RTN
DIS
W ait for Local DCS Substate
DCS
FTT
Training Substate RTN RTP or RTN
CFR
Image Transfer State MCF End of image
Post Image Transfer State MPS
EOM EOP
MPS Substate
EOP Substate RTP or MCF
EOM Substate
NOTE: not all transitions and states are shown
Disconnect Substate 2
Figure 6.1-1. IWF TX Fax Layer States in a Mobile Receiving Fax Call
3 4
6.1.1
5
6.1.1.1 Wait For Remote DIS Substate
6
The IWF shall process messages from the MT2 as follows:
7 8 9
•
IWF Connecting State
If the message is a Start CED Message (see 7.2.5), the IWF shall send CED tone to the PSTN fax machine except when the IWF enters this substate at the beginning of a call where CED tone was already sent during call set-up. After CED has been
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C.S0017-007-A v1.0
sent, the IWF shall remain silent for T9 before transmitting further signals to the PSTN fax machine. The IWF shall remain in this substate.
1 2 3
•
If the message is a Control Message (see 7.2.1) and it is the first Control Message since the beginning of the fax call, the IWF shall send CED tone to the PSTN fax machine if Phase A tones are required and CED tone has not already been sent. After CED has been sent, the IWF shall remain silent for T9 before transmitting further signals to the PSTN fax machine. The IWF shall process the Control Message as specified below.
•
If the message is an NSF, the IWF shall examine the capabilities advertised in the message. If the IWF cannot support any of the options in the message, the IWF shall either discard the message or modify the contents to inhibit such options. If not discarded, the IWF shall encapsulate this NSF message in the IWF NSF message as described in 7.1.3.1 and store this IWF NSF message. The IWF shall remain in this substate.
•
If the message is a CSI, the IWF shall store the message and remain in this substate.
•
If the message is a DIS, the IWF shall modify the bits of the message in accordance with section 10, store the message, and remain in this substate.
•
If any of the above messages is a final frame message, the IWF shall send all stored messages to the PSTN fax machine in the order that they were received from the MT2. If the IWF has no stored IWF NSF message to send, the IWF shall generate and send an IWF NSF message22 preceding the stored messages. Upon receiving a response from the PSTN fax machine, the IWF shall enter the Wait For Local DCS Substate of the IWF Connecting State.
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
6.1.1.2 Wait For Local DCS Substate
26
If the IWF enters this substate from any substate other than the Training Substate, the IWF shall clear transmitter trained flag (see 6.1.4.1) and receiver trained flag (see 6.1.4.2).
27
29
If a message from the MT2 arrives at the IWF when either the IWF is servicing a response from the PSTN fax machine or collision timer has expired, the IWF shall store the message.
30
The IWF shall process messages from the PSTN fax machine as follows:
28
31 32 33 34
•
If the message is a TSI, and it is the first TSI received by the IWF since receiving a DIS or DTC from the MT2, the IWF shall forward this message to the MT2 and remain in this substate. If the message is a TSI but not the first TSI, the IWF shall discard the message and remain in this substate.
22 The inserted IWF NSF shall not contain an Encapsulated TE2 Non-Standard Facilities information
element (see 7.1.3.1).
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C.S0017-007-A v1.0 •
3
If the message is a DCS, and it is the first DCS received by the IWF since receiving a DIS or DTC from the MT2, the IWF shall perform the following in the order specified:
4
−
Store a copy of the DCS.
5
−
Send the DCS to the MT2.
6
−
Set receiver rate (see 6.1.5.1) equal to the rate specified in the DCS.
7
−
Clear receiver trained flag and transmitter trained flag.
8
−
Set transmitter rate (see 6.1.5.2) to the rate specified in the DCS.
9
−
Wait for TCF from the PSTN fax machine. If the training attempt is successful, the IWF shall set transmitter trained flag.
−
Enter the Training Substate of the IWF Connecting State.
1 2
10 11
•
14
If the message is a DCS, and it is not the first DCS received by the IWF since receiving a DIS or DTC from the MT2, the IWF shall perform the following in the order specified:
15
−
Set transmitter rate to the rate specified in the DCS.
16
−
Wait for TCF from the PSTN fax machine. If the training attempt is successful, the IWF shall set transmitter trained flag.
−
Enter the Training Substate of the IWF Connecting State.
12 13
17 18
•
If the message is an NSC, NSF, CIG, CSI, DTC, or DIS, the IWF shall enter the Wait for Local DIS Substate of the IWF Connecting State under the IWF Procedures of a Mobile Transmitting Fax Call (see 6.2.1.1).
•
23
If the message is an NSS, the IWF shall check if the message is an IWF NSS (see 7.1.3.2) and perform the following procedures:
24
−
If the message is not an IWF NSS, the procedures to be followed are left up to the IWF manufacturer.
−
If the message is an IWF NSS, this shall indicate to the IWF that this is a tandem call. The IWF shall examine any information elements to determine and enable the IWF facilities selected by the other IWF. If the IWF receives a NonStandard IWF Facilities Set-up information element, the procedures to be followed are left up to the IWF manufacturer. If the IWF does not receive a NonStandard IWF Facilities Set-up information element, the IWF shall remain in this substate and shall not forward the IWF NSS message to the MT2.
19 20 21 22
25 26 27 28 29 30 31 32 33
6.1.1.3 Training Substate
34 35
If a message from the MT2 arrives at the IWF when either the IWF is servicing a response from the PSTN fax machine or collision timer has expired, the IWF shall store the message.
36
The IWF shall execute the following procedures in the order specified:
37
•
The IWF shall process all stored messages from the MT2 as follows:
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C.S0017-007-A v1.0
1
−
If the message is a CFR, the IWF shall set receiver trained flag.
2
−
If the message is an FTT, the IWF shall check receiver rate. If receiver rate is above the lowest possible modulation rate23, the IWF shall decrement receiver rate to the next lower rate. If receiver rate is at the lowest possible modulation rate, the IWF shall not modify receiver rate.
3 4 5 6
•
7
The IWF shall compare the modulation rate of the PSTN fax machine24 with receiver rate. If any of the following conditions are met, the IWF shall send an FTT to the PSTN fax machine and enter the Wait for Local DCS Substate of the IWF Connecting State.
8 9
−
The PSTN fax machine modulation rate is greater than the TE2 modulation rate (transmitter rate > receiver rate).
−
The PSTN fax machine modulation rate is greater than the rate specified in the Max Rate Message.
14
−
The transmitter is not trained (Transmitter Trained Flag is not set).
15
If none of the above conditions are met, the IWF shall check receiver trained flag.
16
−
If receiver trained flag is set, the IWF shall send a CFR to the PSTN fax machine and enter the Image Transfer State.
−
If receiver trained flag is not set and if three consecutive DCS-TCF messages from the PSTN fax machine are unanswered, the IWF shall send an FTT to the PSTN fax machine and enter the Wait For Local DCS Substate of the IWF Connecting State.
−
If receiver trained flag is not set and if the number of unanswered DCS-TCF messages from the PSTN fax machine is less than three, the IWF shall enter the Wait For Local DCS Substate of the IWF Connecting State.
10 11 12 13
17 18 19 20 21 22 23 24 25
6.1.2
Image Transfer State
26
The IWF shall process image data from the PSTN fax machine as follows: •
Receive image data at the rate specified in the last DCS message from the PSTN fax machine (transmitter rate). The IWF shall be able to receive this image data with no fill bits, i.e., image data sent with an MSLT requirement of 0 ms.
30
•
Send image data to the MT2 in a Data Message (see 7.2.2).
31
•
Strip fill bits from the image data before forwarding the data to the MT2.
27 28 29
23 The lowest rate is determined from the DIS or DTC received from the MT2. 24 The IWF shall determine the modulation rate of the PSTN fax machine from the most recently
received DCS.
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C.S0017-007-A v1.0 •
3
Terminate the Data Message with an HDLC flag and enter the Post Image Transfer State upon detecting the end of image data from the PSTN fax machine. The end of image data shall occur when any of the following is detected by the IWF:
4
−
RTC.
5
−
Drop of high rate carrier.
6
−
V.21 preamble (belonging to the proceeding EOP, MPS, or EOM message or their corresponding PRI versions).
1 2
7 8
6.1.3
9
12
Upon entry into this state, the IWF shall wait for post-page messages from the PSTN fax machine. If the IWF detects V.21 preamble on the PSTN interface for T8 continuously and the IWF has not sent a Preamble Message to the MT2 since entering this state, the IWF shall send a Preamble Message over the Um interface. Upon receiving the rest of the
13
message from the PSTN fax machine, the IWF shall transmit the message to the MT2.
14
The IWF shall process the message from the PSTN fax machine as follows:
10 11
Post Image Transfer State
15
•
If the message is an EOP, the IWF shall enter the EOP Substate.
16
•
If the message is an MPS, the IWF shall enter the MPS Substate.
17
•
If the message is an EOM, the IWF shall enter the EOM Substate.
18
•
If the message is a procedure interrupt (PRI-XXX), the IWF shall send the message to the MT2 and remain in the Post Image Transfer State.
19 20 21 22 23 24 25
In the following substates of the Post Image Transfer State, the IWF shall monitor the PSTN fax machine for repeated post-page messages. If the IWF receives a total of three (3) postpage messages from the PSTN fax machine, the IWF shall start timer T13. Upon expiration of T13, the IWF shall start sending V.21 preamble to the PSTN fax machine if a response has not been sent. The IWF shall continue to send the V.21 preamble until it has a response to send to the PSTN fax machine.
28
In the following substates of the Post Image Transfer State, if the message received from the MT2 is a PIN or PIP, the IWF shall send a DCN to the PSTN fax machine. The IWF shall also send a DCN to the MT2 and direct the analog interface to release the call.
29
6.1.3.1 EOP Substate
30
The IWF shall process messages from the MT2 as follows:
26 27
31
•
If the message is an MCF or RTP, the IWF shall send the message to the PSTN fax machine and enter the Disconnect Substate.
•
If the message is an RTN, the IWF shall send the message to the PSTN fax machine and enter the Wait For Local DCS Substate of the IWF Connecting State.
32 33 34 35
6.1.3.2 MPS Substate
36
The IWF shall process messages from the MT2 as follows:
37 38
•
If the message is an MCF, the IWF shall send the message to the PSTN fax machine and enter the Image Transfer State.
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C.S0017-007-A v1.0
1
•
2
If the message is an RTP or RTN, the IWF shall send the message to the PSTN fax machine and enter the Wait For Local DCS Substate of the IWF Connecting State.
3
6.1.3.3 EOM Substate
4
6
The IWF shall wait for a message from the MT2. If the message is an MCF, RTP, or RTN, the IWF shall send the message to the PSTN fax machine and enter the Wait for Remote DIS Substate of the IWF Connecting State.
7
6.1.3.4 Disconnect Substate
8
If the IWF receives a DCN from the PSTN fax machine, the IWF shall discard the DCN, close the transport layer, and direct the analog interface to release the call.
5
9
11
If the IWF does not receive a DCN from the PSTN fax machine within T11, the IWF shall close the transport layer and direct the analog interface to release the call.
12
6.1.4
13
6.1.4.1 Transmitter Trained Flag
14
This flag is set by the IWF when the IWF receives a valid TCF from the PSTN fax machine.
15
6.1.4.2 Receiver Trained Flag
16
This flag is set by the IWF when the IWF receives a CFR from the MT2.
17
6.1.5
18
6.1.5.1 Receiver Rate
19
The current modulation rate being negotiated between the MT2 and the TE2.
20
6.1.5.2 Transmitter Rate
21
The current modulation rate being negotiated between the IWF and the PSTN fax machine.
10
Flags
Rates
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1
6.2
Mobile Transmitting Fax
Wait for Local DIS Substate MCF, RTP, or RTN
DIS
Wait for Remote DCS Substate
DCS FTT Wait for Local CFR/FTT Substate
CFR
RTP or RTN
Image Transfer State MCF End of image
Post Image Transfer State MPS
EOM EOP
MPS Substate RTN
EOP Substate RTP or MCF
EOM Substate
NOTE: not all transitions and states are shown
End call
2
Figure 6.2-1. IWF RX Fax Layer States in a Mobile Transmitting Fax Call
3 4
6.2.1
5
6.2.1.1 Wait for Local DIS Substate
6
The IWF shall process the messages from the PSTN fax machine as follows:
7 8 9
•
IWF Connecting State
If the message is an NSF or NSC, the IWF shall check if the message is an IWF NSF or IWF NSC (see 7.1.3.1) and remain in this substate after performing the following procedures:
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C.S0017-007-A v1.0
1
−
If the message is not an IWF NSF or IWF NSC, the IWF shall examine the capabilities advertised in the message. If the IWF cannot support any of the options in the message, the IWF shall either discard the message or modify the contents to inhibit such options. If not discarded, the IWF shall store this message.
−
If the message is an IWF NSF or IWF NSC, this shall indicate to the IWF that this is a tandem call. If the message contains an Encapsulated Non-Standard Facilities information element, the IWF shall examine the capabilities advertised. If the IWF cannot support any of the options in the information element, the IWF shall either discard the information element or modify the contents to inhibit such options. If not discarded, the IWF shall store this information element as an NSF or NSC message25.
2 3 4 5 6 7 8 9 10 11 12 13
•
If the message is a CSI, DIS, CIG, or DTC, the IWF shall store the message and remain in this substate.
•
If any of the above messages is a final frame message and all the stored messages were received correctly, the IWF shall forward all the stored messages to the MT2 in the order that they were received from the PSTN fax machine and enter the Wait For Remote DCS Substate of the IWF Connecting State.
14 15 16 17 18 19
6.2.1.2 Wait for Remote DCS Substate
20
The IWF shall process messages received over the Um interface as follows:
21
•
If the message is a TSI, CIG, or CSI, the IWF shall store the message and remain in this substate.
•
If the message is a DCS, the IWF shall enter the Wait for Local CFR/FTT Substate of the IWF Connecting State.
•
If the message is an NSC or NSF, the IWF shall examine the capabilities advertised in the message. If the IWF cannot support any of the options in the message, the IWF shall either discard the message or modify the contents to inhibit such options. If not discarded, the IWF shall store the message. The IWF shall remain in this substate.
•
If the message is a DTC or DIS, the IWF shall modify the bits of the message in accordance with section 10. The IWF shall then send NSC or NSF (if any stored), CIG or CSI (if any stored), and DTC or DIS to the PSTN fax machine in the order the messages were received from the MT2. Upon receiving a response from the PSTN fax machine, the IWF shall enter the Wait For Local DCS Substate of the IWF Connecting State under the IWF Procedures of a Mobile Receiving Fax Call (see 6.1.1.2).
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
25 The IWF shall only store the Encapsulated TE2 Non-Standard Facilities information element for
forwarding to the MT2. The rest of the IWF NSF or IWF NSC message shall not be sent to the MT2.
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C.S0017-007-A v1.0
1
•
2
If the message is an NSS, the procedures to be followed are left up to the IWF manufacturer.
3
6.2.1.3 Wait for Local CFR/FTT Substate
4
If this substate is entered from the Wait for Remote DCS Substate, the IWF shall perform the following procedures on the DCS received from the MT2:
5
•
Set the rate bits 11, 12, 13, and 14 to ‘1000’ if the rate bits 11, 12, 13, and 14 of the DIS/DTC advertised by the PSTN fax machine were ‘1000’ (i.e. the PSTN fax machine is only capable of V.29 modulation).
9
•
Set the MSLT bits 21, 22, and 23 in accordance with Table 6.2.1.3-1.
10
•
Store a copy of the modified DCS.
11
•
Send the stored TSI (if any) and the modified DCS to the PSTN fax machine. If the IWF is in a tandem call, the IWF shall precede these messages with the IWF NSS message.
6 7 8
12 13
Table 6.2.1.3-1. MSLT Resetting in the DCS
14
15 16 17 18 19 20 21 22 23 24 25
MSLT bits advertised by the PSTN fax machine
New MSLT bits if DCS bit 15 = 0
New MSLT bits if DCS bit 15 = 1
000
000
000
001
001
001
010
010
010
100
100
100
011
010
100
110
000
010
101
001
000
111
111
111
If this substate is entered from either the MPS Substate or the EOP Substate of the Post Image Transfer State, the IWF shall send the last stored TSI (if any) and the last stored DCS to the PSTN fax machine. After sending a DCS to the PSTN fax machine, the IWF shall wait for T2 and then generate and send TCF to the PSTN fax machine at the modulation rate specified in the DCS. The IWF shall then process messages from the PSTN fax machine as follows: •
If the message is an FTT, the IWF shall forward the message to the MT2. The IWF shall then set the modulation rate in the DCS (bits 11, 12, 13, 14) to the next lower rate, store a copy of the DCS, and send the stored TSI (if any) and the DCS followed by a TCF to the PSTN fax machine. The TCF shall be sent by the IWF at the modulation rate specified in the DCS after maintaining silence for a period of T2
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C.S0017-007-A v1.0
after the DCS is sent. The IWF shall remain in this substate.
1 2
If an FTT is received again, the IWF shall repeat this process until a CFR is received, or until 6 attempts have been made at the lowest supported modulation rate26. If an FTT is received after 6 attempts at the lowest supported modulation rate, the IWF shall send DCN to the PSTN fax machine and the MT2. The IWF shall direct the analog interface to release the call.
3 4 5 6 7 8
•
9
If the message is a CFR, the IWF shall enable page start timer, T6, and send the CFR to the MT2. The IWF shall enter the Image Transfer State.
10
6.2.2
11
The IWF shall process messages from the MT2 as follows: •
Image Transfer State
13
The IWF shall monitor for a Data Message in order to detect the incoming image data.
14
−
If page start timer (T6) expires, the IWF shall generate and send blank scan lines (see ITU-T T.4 4.1) in T3 intervals to the PSTN fax machine until image data is received from the MT2. The IWF should maintain a count of inserted blank scan lines and use this to maintain a fixed number of lines27 in the page.
−
If the image data is received before page start timer expires, the IWF shall send the image data to the PSTN fax machine.
12
15 16 17 18 19 20
•
The IWF shall not transmit the address, control, and flag fields of the received Data Message over the PSTN interface.
•
The IWF shall transmit image data to the PSTN fax machine at the last modulation rate accepted by the PSTN fax machine. If the IWF is not in a tandem call, the IWF shall transmit image scan lines to the PSTN fax machine at intervals that meet the PSTN fax machine MSLT requirement. If the IWF is in a tandem call, the IWF shall transmit these lines with an MSLT of 0 ms, i.e., the IWF shall not insert fill bits unless it has no lines to send.
•
If the IWF does not have image data to send to the PSTN fax machine, the IWF shall insert fill bits. When fill bits are inserted, the duration of each image scan line shall not exceed T3.
•
The IWF shall monitor the received HDLC information for an HDLC flag which indicates the end of the image data. Upon detecting the end of image data, the IWF shall drop the high rate carrier to the PSTN fax machine then remain silent on the
21 22 23 24 25 26 27 28 29 30 31 32 33
26 The lowest rate is determined from the DIS or DTC received from the PSTN fax machine. 27 There is space for a fixed number of lines in a standard size page (i.e. fixed page size). The IWF
should extract the vertical resolution and page size parameters from the stored DCS and compute the number of lines allowed. If the receiving fax machine uses an unlimited page size (such as a thermal paper roll), it may not be necessary to delete any lines from the page.
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C.S0017-007-A v1.0
PSTN interface for a period of at least T4. The IWF shall then enter the Post Image Transfer State.
1 2 3
•
4 5
If the IWF receives a DCN over the Um interface, the IWF shall stop transmitting any image data to the PSTN fax machine and send V.21 preamble before forwarding the message to the PSTN fax machine.
6
6.2.3
Post Image Transfer State
7
The IWF shall process messages from the MT2 as follows:
8
•
If the message is an EOP, the IWF shall enter the EOP Substate.
9
•
If the message is an MPS, the IWF shall enter the MPS Substate.
10
•
If the message is an EOM, the IWF shall enter the EOM Substate.
11
•
If the message is a procedure interrupt (PRI-XXX), the IWF shall discard the message and send a DCN to the PSTN fax machine. The IWF shall also send a DCN to the MT2 and direct the analog interface to release the call.
12 13
16
In all the substates below (6.2.3.1, 6.2.3.2, and 6.2.3.3), if the message received from the PSTN fax machine is a PIN or PIP, the IWF shall forward the message to the MT2 and remain in the same substate.
17
6.2.3.1 EOP Substate
18
Upon entry to this substate, the IWF shall send the EOP to the PSTN fax machine. The IWF shall then process messages from the PSTN fax machine as follows:
14 15
19 20
•
If the message is an MCF or RTP, the IWF shall send the message to the MT2 and wait for a period of T1. The IWF shall then send a DCN to the PSTN fax machine and direct the analog interface to release the call.
•
If the message is an RTN, the IWF shall send the message to the MT2 and enter the Wait For Local CFR/FTT Substate of the IWF Connecting State.
21 22 23 24 25
6.2.3.2 MPS Substate
26
Upon entry to this substate, the IWF shall send the MPS to the PSTN fax machine. The IWF shall then process messages from the PSTN fax machine as follows:
27 28
•
If the message is an MCF, the IWF shall enable page start timer (T6, see 9), send the MCF to the MT2, and enter the Image Transfer State.
•
If the message is an RTP or RTN, the IWF shall forward the message to the MT2 and enter the Wait For Local CFR/FTT Substate of the IWF Connecting State.
29 30 31 32
6.2.3.3 EOM Substate
33
Upon entry to this substate, the IWF shall send the EOM to the PSTN fax machine and wait for a response. If the message from the PSTN fax machine is an MCF, RTP or RTN, the IWF shall send the message to the MT2 and enter the Wait For Local DIS Substate of the IWF Connecting State.
34 35 36
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C.S0017-007-A v1.0
1
7
2
7.1
3
6
These messages are exchanged between the Analog Fax Layer and the transmitting or receiving fax machine through the RJ-11 or PSTN interface. The format of these messages is specified in T.30. The following descriptions are provided for informational purposes only.
7
7.1.1
8
V.21 messages refer to the T.30 control messages transmitted using ITU-T V.21 modulation over the analog interface. These messages are formatted according to an HDLC frame structure as specified in 5.3 of T.30. A single frame is shown in Figure 7.1-1.
4 5
9 10
MESSAGES Messages Over the Analog Interface
V.21 Messages
11
Preamble
Flag
Flag
Address
T.30 Message
Control
HDLC Information Field
FCS
Flag
12
Figure 7.1-1. T.30 V.21 Message Format
13 14 15 16 17 18 19 20 21 22 23 24 25 26
The preamble precedes all binary coded signaling whenever new transmission of information begins in any direction (see T.30 5.3.1). The preamble for binary coded signaling at 300 bps is a series of HDLC flags for 1s ± 15% (see T.30 5.3.1.1). The HDLC flag is an octet (0x7e) used to denote the beginning and end of the frame. The trailing flag of one frame may be the leading flag of the following frame (see T.30 5.3.3). The address field is set to 0xff in all the T.30 messages (see T.30 5.3.4). The control field represented in binary is of the form '1100 X000', where X=0 represents non-final frames, while X=1 represents final frames (see T.30 5.3.5). The HDLC information field is of variable length and incorporates specific information for the control and message interchange between two facsimile machines. This field is further divided into two parts, the facsimile control field (FCF) and the facsimile information field (FIF). The values and details regarding these fields are specified in 5.3.6.1 and 5.3.6.2 of T.30.
28
The FCS is a 16 bit sequence number used for error detection. The FCS covers the address, control and information fields of the T.30 message (see T.30 5.3.7).
29
7.1.2
30
This refers to the digitally scanned image sent from the transmitting fax machine to the receiver fax machine. The image is coded according to the appropriate T.4 image
27
31
Image Data
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2
compression procedures and transmitted using the selected ITU-T V series modulation standard.
3
7.1.3
4 5
These are V.21 messages exchanged between IWF’s across the PSTN in a tandem analog fax call.
6
7.1.3.1 IWF NSF and IWF NSC Messages
7
The IWF uses the IWF NSF and IWF NSC messages to identify itself as an Analog Fax IWF. The messages also allow the IWF to advertise options that are specific to IWF fax modems. These messages are sent only to the PSTN and formatted according to Table 7.1.3.1-1.
1
8 9 10
11
IWF Identification and Capabilities Messages
Table 7.1.3.1-1. IWF NSF and IWF NSC Message Format
FLAG
ADDRESS
-
CONTROL
-
FCF
-
FIF
-
22
FCS
-
1
FCF
1
FIF
variable
FCS
2 1
Address field.
Control field.
Facsimile control field.
Facsimile information field.
Frame checking sequence. These two octets shall be set according to the procedures of 5.3.7 of T.30.
24 25
27
CONTROL
The octets in this field shall be formatted according to Table 7.1.3.1-2.
21
26
1
This octet shall be set to 0x04 for an NSF message and 0x84 for an NSC message.
19
23
ADDRESS
This octet shall be set to 0xc0.
18
20
1
This octet shall be set to 0xff.
16 17
FLAG
This octet shall be set to 0x7e.
14 15
Length (octets)
FLAG - HDLC frame delimiter.
12 13
Field
FLAG
-
HDLC frame delimiter. This octet shall be set to 0x7e.
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C.S0017-007-A v1.0
1
Table 7.1.3.1-2. FIF Format for the IWF NSF and IWF NSC Messages Field
2
Length (octets)
COUNTRY
1
MANUF
2
Followed by zero or more instances of the following information element:
3
TYPE
1
LENGTH
1
INFO
Variable
4
6
The T.30 field which identifies the country where the manufacturer code was granted.
7
This octet shall be set to 0xb5.
5
8
COUNTRY
MANUF
-
-
9
These two octets shall be set to 0x00a6 to identify the fax equipment as an Analog Fax IWF.
10 11 12
The T.30 field which identifies the manufacturer of the fax equipment.
TYPE
-
The type of information element.
13
This octet shall be set to:
14
0x00 - for the IWF Facilities information element. This information element identifies the standardized facilities of the IWF.
15 16
0x01 - for the Non-Standard IWF Facilities information element. This information element identifies non-standard (manufacturer specific) facilities of the IWF.
17 18 19
0x02 - for the Encapsulated TE2 Non-Standard Facilities information element. This information element represents the non-standard facilities advertised by the TE2 and relayed by the MT2 to the IWF.
20 21 22 23 24
LENGTH
-
This shall indicate the number of octets28 in the INFO field of the information element.
25 26 27 28 29
Length of the INFO field in the information element.
INFO
-
Information field for the information element. When TYPE=0x00, the INFO field shall be formatted according to Table 7.1.3.1-3.
28 The length shall indicate the number of octets prior to T.30 bit-stuffing.
7-3
C.S0017-007-A v1.0 When TYPE=0x01, the INFO field shall be formatted according to Table 7.1.3.1-4.
1 2
When TYPE=0x02, the INFO field shall contain the NSF or NSC message from the MT2 and shall be formatted according to Table 7.2.1.1-5.
3 4 5 6 7
Table 7.1.3.1-3. INFO Field Format for TYPE=0x00 Information Element Field
8
RESERVED
Length (octets)
RESERVED - Reserved bits.
1
This octet shall be set to 0x00.
9 10 11
Table 7.1.3.1-4. INFO Field Format for TYPE=0x01 Information Element Field
Length (octets)
IWF_MANUF
12
IWF_MANUF
NS_OPTIONS Variable - Identifies the manufacturer of the IWF. This octet shall be set to the manufacturer’s code as described in TSB58.
13 14 15
1
NS_OPTIONS
-
Non-standard options. The format of these octets is not standardized and shall be defined according to the IWF manufacturer’s protocol.
16 17 18 19
Table 7.1.3.1-5. INFO Field Format for TYPE=0x02 Information Element Field
Length (octets)
ADDRESS
1
CONTROL
1
FCF
1
FIF
variable
FCS
2
These fields shall be set according to the corresponding fields in the NSF or NSC message received from the MT2.
20 21 22 23
7.1.3.2 IWF NSS Message
24
The IWF uses the IWF NSS message to identify itself as an Analog Fax IWF to another IWF that has sent an IWF NSF or IWF NSC. The message also allows the IWF to select options
25
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C.S0017-007-A v1.0
1 2
that are specific to IWF fax modems. This message is sent only to another CDMA IWF and formatted according to table 7.1.3.2-1. Table 7.1.3.2-1. IWF NSS Message Format
3
4
FLAG
ADDRESS
-
CONTROL
-
FCF
-
FIF
-
15
FCS
-
18
21
1
FCF
1
FIF
variable
FCS
2
Address field.
Control field.
Facsimile control field.
Facsimile information field.
Frame checking sequence.
FLAG
-
HDLC frame delimiter. This octet shall be set to 0x7e.
Table 7.1.3.2-2. FIF Format for the IWF NSS Message Field
22
1
These two octets shall be set according to the procedures of 5.3.7 of T.30.
17
20
CONTROL
The octet(s) in this field shall be formatted according to Table 7.1.3.2-2.
14
19
1
This octet shall be set to either 0x44 or 0xc4 as described in 5.3.6.1 and 5.3.6.1.3 of T.30.
12
16
ADDRESS
This octet shall be set to 0xc0.
11
13
1
This octet shall be set to 0xff.
9 10
FLAG
This octet shall be set to 0x7e.
7 8
Length (octets)
FLAG - HDLC frame delimiter.
5 6
Field
Length (octets)
COUNTRY
1
MANUF
2
Followed by zero or more instances of the following information element:
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C.S0017-007-A v1.0
TYPE
1
LENGTH
1
INFO
variable
1
3
The T.30 field which identifies the country where the manufacturer code was granted.
4
This octet shall be set to 0xb5.
2
5
COUNTRY
MANUF
-
-
6
These two octets shall be set to 0x00a6 to identify the fax equipment as an Analog Fax IWF.
7 8 9
The T.30 field which identifies the manufacturer of the fax equipment.
TYPE
-
Describes the type of information element.
10
This octet shall be set to:
11
0x00 - for the IWF Digital Command Signal information element. This information element selects standardized capabilities advertised by the other IWF in the IWF Facilities information element of its IWF NSF or IWF NSC message.
12 13 14
0x01 - for the Non-Standard IWF Facilities Set-up information element. This information element selects nonstandard (manufacturer specific) capabilities advertised by the other IWF in the Non-Standard IWF Facilities information element of its IWF NSF or IWF NSC message.
15 16 17 18 19 20
LENGTH
-
This shall indicate the number of octets29 in the INFO field of the information element.
21 22 23
INFO
-
Information field for the information element. When TYPE=0x00, the INFO field shall be formatted according to Table 7.1.3.2-3.
24 25
When TYPE=0x01, the INFO field shall be formatted according to Table 7.1.3.2-4.
26 27 28
Length of the INFO field in the information element.
Table 7.1.3.2-3. INFO Field Format for TYPE=0x00 Information Element Field
29 30
RESERVED
Length (octets)
RESERVED - Reserved bits.
1
This octet shall be set to 0x00.
29 The length shall indicate the number of octets prior to T.30 bit-stuffing.
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C.S0017-007-A v1.0
Table 7.1.3.2-4. INFO Field Format for TYPE=0x01 Information Element
1
Field
Length (octets)
IWF_MANUF IWF_MANUF
2
-
1
NS_OPTIONS variable Identifies the manufacturer of the IWF. This octet shall be set to the manufacturer’s code as described in TSB58.
3 4
NS_OPTIONS
5
-
Non-standard options. The format of these octets is not standardized and shall be set according to the IWF manufacturer’s protocol.
6 7 8
7.2
9 10
These messages are exchanged between the Analog Fax Layers in the IWF and the MT2. These messages shall be formatted as follows30:
11
7.2.1
12
14
These messages correspond to T.30 V.21 messages that are received from either the PSTN fax machine or the TE2. When the Analog Fax Layer receives a V.21 message that is to be forwarded over the Um interface, the Analog Fax Layer shall wait to receive the entire V.21
15
message, and then generate a corresponding Control Message as follows:
13
16
Messages over the Um Interface
•
Send one HDLC flag over the Um interface (preamble shall not be sent over the Um interface).
•
Forward the values of the ADDRESS, CONTROL, FCF, FIF, and FCS fields of the V.21message over the Um interface.
•
Send one HDLC flag over the Um interface to indicate the end of the Control Message.
17 18 19 20 21
Control Messages
30 The format of these messages is similar to the T.30 HDLC frame structure for V.21 messages.
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C.S0017-007-A v1.0
Table 7.2.1-1. Control Message Format
1
FLAG
2
-
Field
Length (octets)
FLAG
1
ADDRESS
1
CONTROL
1
FCF
1
FIF
variable
FCS
2
FLAG HDLC frame delimiter.
1
This octet shall be set to 0x7e.
3
ADDRESS
4
-
Address field. This octet shall be set to the address field of the received V.21 message.
5 6
CONTROL
7
-
Control field. This octet shall be set to the control field of the received V.21 message.
8 9
FCF
10
-
Facsimile control field. This octet shall be set to the facsimile control field of the received V.21 message.
11 12
FIF
13
-
Facsimile information field. The octet(s) in this field shall be set to the facsimile information field of the received V.21 message. In some states, the Analog Fax Layer may be required to modify the contents of this field before forwarding it over the Um interface.
14 15 16 17 18
FCS
19
-
Frame checking sequence. These two octets shall be set according to the procedures of 5.3.7 of T.30.
20 21
FLAG
22
-
HDLC frame delimiter. This octet shall be set to 0x7e.
23 24
7.2.2
25
A Data Message corresponds to a single page of image data received from the transmitting fax machine. Image data for a single page is sent in one Data Message (a single HDLC frame31) that is assembled and formatted at the TX Fax Layer.
26 27
Data Message
31 A single HDLC frame may be carried over the U interface in multiple packets or datagrams. m
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C.S0017-007-A v1.0
Table 7.2.2-1. Data Message Format
1
Field
Length (octets)
FLAG
1
ADDRESS
1
CONTROL
1
IMAGE_DATA FLAG
2
variable
FLAG - HDLC frame delimiter.
1
Upon detecting the start of image data from the transmitting fax machine, the TX Fax Layer shall set this octet to 0x7e and send it over the Um interface.
3 4 5
ADDRESS
6
-
Address field. The TX Fax Layer shall set this octet to 0xFF.
7
CONTROL
8
-
Control field. The TX Fax Layer shall set this octet to 0x50 to indicate that this is a Data Message.
9 10
IMAGE_DATA
11
-
Image Data Field. This field shall contain the image data received by the TX Fax Layer from the transmitting fax machine, including EOL markers and any required escape characters. The TX Fax Layer shall pad this field with 0s if this field does not end on an octet boundary at the end of image data.
12 13 14 15 16
FLAG
17
-
HDLC frame delimiter. The TX Fax Layer shall set this octet to 0x7e.
18 19
7.2.3
20
The Preamble Message is sent over the Um interface to start V.21 preamble at the remote Analog Fax Layer. When the IWF receives the Preamble Message over the Um interface, the
21 22 23 24 25
Preamble Message
IWF shall immediately start sending V.21 preamble to the PSTN fax machine. Similarly, when the MT2 receives the Preamble Message over the Um interface, the MT2 shall immediately start sending V.21 preamble to the TE2. The Preamble Message shall be formatted as specified in Table 7.2.3-1.
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C.S0017-007-A v1.0
Table 7.2.3-1. Preamble Message Format
1
FLAG
2
-
Field
Length (octets)
FLAG
1
ADDRESS
1
CONTROL
1
FCF
1
FIF
1
FCS
2
FLAG HDLC frame delimiter.
1
This octet shall be set to 0x7e.
3
ADDRESS
4
-
Address field. This octet shall be set to 0xFF.
5
CONTROL
6
-
Control field. This octet shall be set to 0x51.
7
FCF
8
-
Facsimile control field. This octet shall be set to 0x01.
9
FIF
10
-
Facsimile information field. This octet shall be set to 0x00.
11
FCS
12
-
Frame checking sequence. These two octets shall be set according to the procedures of 5.3.7 of T.30.
13 14
FLAG
15
-
HDLC frame delimiter. This octet shall be set to 0x7e.
16 17
7.2.4
18
The Max Rate Message is sent by the IWF to the MT2 after the initial OK response from the IWF (see 4.1.1, 4.1.2, 4.1.3). The message shall be formatted as specified in Table 7.2.4-1.
19
Max Rate Message
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C.S0017-007-A v1.0
Table 7.2.4-1. Max Rate Message Format
1
2
FLAG
-
ADDRESS
-
CONTROL
-
FCF
-
FIF
-
1
CONTROL
1
FCF
1
FIF
1
FCS
2
FLAG HDLC frame delimiter.
1
Address field.
Control field.
Facsimile control field.
Facsimile information field. The IWF shall set the 4 most significant bits of this field according to Table 7.2.4-2. The least significant 4 bits are reserved and shall be set to zero.
11 12 13 14
ADDRESS
The IWF shall set this octet to 0x00.
9 10
1
The IWF shall set this octet to 0x51.
7 8
FLAG
The IWF shall set this octet to 0xff.
5 6
Length (octets)
The IWF shall set this octet to 0x7e.
3 4
Field
Table 7.2.4-2. FIF Values for the Max Rate Message Most significant 4 bits of the FIF (binary)
Maximum fax rate supported
0000
Reserved
0001
2400
0010
4800
0011
7200
0100
9600
0101
12000
0110
14400
(bits/second)
15 16 17 18
FCS
-
Frame checking sequence. The IWF shall set these two octets according to the procedures of 5.3.7 of T.30.
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1
-
HDLC frame delimiter. The IWF shall set this octet to 0x7e.
2 3
7.2.5
4
The Start CED Message should be sent by the RX Fax Layer to the TX Fax Layer to start the generation of CED tone to the transmitting fax machine32.
5
Start CED Message
Table 7.2.5-1. Start CED Message Format
6
Field
Length (octets)
FLAG
1
ADDRESS
1
CONTROL
1
FCF
1
FIF
1
FCS
2
FLAG
1
7 8
FLAG
-
This octet shall be set to 0x7e.
9 10
ADDRESS
-
CONTROL
-
FCF
-
FIF
-
FCS
-
20
22
Frame checking sequence. These two octets shall be set according to the procedures of 5.3.7 of T.30.
19
21
Facsimile information field. This octet shall be set to 0x00.
17 18
Facsimile control field. This octet shall be set to 0x02.
15 16
Control field. This octet shall be set to 0x51.
13 14
Address field. This octet shall be set to 0xff.
11 12
HDLC frame delimiter.
FLAG
-
HDLC frame delimiter. This octet shall be set to 0x7e.
32 By sending a Start CED Message, the call set-up time may be reduced. For example, this
message may be sent when the RX Fax Layer detects CED tone or the preamble of the first V.21 message from the receiving fax machine.
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1
7.3
2
7.3.1
3
7.3.1.1 Control, Preamble, Max Rate, and Start CED Messages
4
When formatting binary data into octets to be sent over the Um interface, the Analog Fax
5
Layer shall follow the bit ordering specified in 5.3 of T.30 (i.e., the binary representation reads with the most significant bit on the left).
6
Formatting octets over the Um interface Bit Format of Octets
8
For example, for a CFR message with Facsimile Control Field set to binary 00100001, the Analog Fax Layer shall send this octet to the transport layer as 0x21.
9
7.3.1.2 Data Messages
7
10 11 12
As the TX Fax Layer receives a stream of image data bits from the transmitting fax machine over its analog interface, the TX Fax Layer shall package the bits into octets starting with the most significant bit first and then proceeding to the least significant bit.
15
For example, when the TX Fax Layer receives the following sequence of bits at the end of an image line, 0000000000011100, the TX Fax Layer shall send the octet 0x00 followed by 0x1c to the transport layer.
16
7.3.2
17
The IWF and MT2 shall perform byte escaping of all HDLC messages sent over the Um interface regardless of the message type (Control, Data, Preamble or Max Rate)33. After computing the Frame Check Sequence (FCS, if any), the IWF and MT2 shall examine the entire frame between the two Flag Sequence Octets and:
13 14
18 19 20
Byte Escaping of Flags
21
•
Replace each Flag Sequence Octet, 0x7e, with the sequence 0x7d 0x5e
22
•
Replace each Control Escape Octet, 0x7d, with the sequence 0x7d 0x5d
23 24
Upon reception of an HDLC message over the Um interface and prior to FCS computation (if any), the IWF and MT2 shall:
25
•
•
26
•
• Exclusive-or (XOR) the octet following each removed Control Escape Octet with 0x20.
27
Remove each Control Escape Octet from the frame
33 The requirements described in this section are derived from RFC 1662, Section 4.2.
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1
8
2
This section contains example call flows that illustrate the operation of the analog fax service under various call scenarios. The examples provided within this section illustrate one means of providing analog fax service. Alternative, standard-compliant means are also possible.
3 4 5
CALL FLOWS
6
PSTN and RJ-11 signals
fax Phase A tones (CNG/CED) or V.21 preamble T.30 V.21 message (when on RJ-11 or PSTN) Um interface message (when between MT2 & BS/MSC/IWF) High rate image/training data
7
Figure 8-1. Message and Signal Representation Used in Call Flows
8 9 10 11 12 13 14 15
8.1
Call Set-Up
Calls may be setup as analog fax calls or they may be setup as voice calls and transitioned to analog fax. In addition, calls may be setup from either station, regardless of which station will be sending the fax image data or the CNG and CED tones. Section 8.1.1 illustrates calls initiated as analog fax calls. Section 8.1.2 illustrates calls initiated as voice calls which transition to analog fax. For completeness, the figures in section 8.1.2 show examples of the voice call setup.
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8.1.1
Calls Originating as Analog Fax
2
TE2
MT2
PSTN
BS/MSC
PSTN Fax off hook
dial tone
start CNG tone ring
Incoming call with dialed digits (AFax DN)
S.O. = Analog Fax
DTMF digits (AFax DN)
start CNG tone (optional)
ring BS/MSC/IW F off hook
Synch TCP/IP-PPP-RLP start CED tone (optional) CNG tone (optional) AT+CFG="" 0 ATA
off hook
CNG tone (optional)
0 V.21 preamble NSF
Max Rate Message
CSI
Start CED Message
DIS
Relay CSI, DIS
start CED tone
V.21 preamble CSI DIS
3 4
Figure 8.1.1-1. Call Set-Up for a Mobile Receiving Fax Call Initiated as Analog Fax
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1 2
TE2
MT2
PSTN
BS/MSC
PSTN Fax
off hook dial tone DTMF digits (AFax dial prefix followed by dialed number) S.O. = Analog Fax
start CNG tone (optional)
BS/MSC/IWF
Synch TCP/IP-PPP-RLP
CNG tone (optional)
AT+CFG="" 0 ATDT
0
originate call to dialed number start CNG tone connect
ring
off hook
Max Rate Message CNG tone (optional) start CED tone
start CED tone (optional) Start CED Message V.21 preamble NSF CSI
V.21 preamble CSI
Relay CSI, DIS
DIS
DIS
3 4
Figure 8.1.1-2. Call Set-Up for a Mobile Transmitting Fax Call Initiated as Analog Fax
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8.1.2 Calls Originating as Voice, then Transitioning to Analog Fax
2
TE2
MT2
PSTN
BS/MSC
PSTN Fax off hook
dial tone Incoming call with dialed digits ring
off hook
DTMF digits (Voice DN)
S.O. = Voice
Connect Order
off hook
start CNG tone (optional)
CNG tone (through vocoders) start CED tone (through vocoders) V.21 preamble NSF CSI
Service Negotiation to S.O. = Analog Fax
DIS BS/MSC/IW F
Synch TCP/IP-PPP-RLP
AT+CFG="" 0
V.21 preamble NSF
AT+CVF= 0,0 0
CSI DIS
Max Rate Message Relay CSI, DIS
V.21 preamble CSI DIS
3 4 5 6
Figure 8.1.2-1. Call Set-Up as Voice Transitioning to Mobile Receiving Fax. Voice Call Shown as Mobile-Terminated and Fax Call Detected Using V.21 Preamble Detection.
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TE2
MT2
PSTN
BS/MSC
PSTN Fax
off hook dial tone
DTMF digits (dialed number) S.O. = Voice
originate call to dialed number
ring
connect
off hook
start CNG tone (through vocoders) start CED tone (through vocoders) V.21 preamble NSF CSI
Service Negotiation to S.O. = Analog Fax
DIS BS/MSC/IWF
Synch TCP/IP-PPP-RLP
AT+CFG="" 0
V.21 preamble
AT+CVF= 0,0
NSF 0 CSI Max Rate Message DIS
Relay CSI, DIS
V.21 preamble CSI DIS
3 4 5 6
Figure 8.1.2-2. Call Set-Up as Voice Transitioning to Mobile Receiving Fax. Voice Call Shown as Mobile-Originated and Fax Call Detected Using V.21 Preamble Detection.
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TE2
MT2
PSTN
BS/MSC
PSTN Fax
off hook dial tone
DTMF digits (dialed number) S.O. = Voice
originate call to dialed number
ring
connect
off hook
start CNG tone (through vocoders)
start CED tone (through vocoders) V.21 preamble NSF
Service Negotiation to S.O. = Analog Fax
CSI DIS BS/MSC/IWF
Synch TCP/IP-PPP-RLP
AT+CFG="" 0 AT+CVFQ? +CVFQ: 1,0
V.21 preamble NSF
Max Rate Message CSI V.21 preamble
Relay CSI, DIS
DIS
CSI DIS
3 4 5 6
Figure 8.1.2-3. Call Set-Up as Voice Transitioning to Mobile Transmitting Fax. Voice Call Shown as Mobile-Originated and Fax Call Detected Using V.21 Preamble Detection.
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TE2
MT2
PSTN
BS/MSC
PSTN Fax off hook
dial tone Incoming call with dialed digits ring
off hook
DTMF digits (Voice DN)
S.O. = Voice
Connect Order
off hook
CNG tone (through vocoders) start CED tone (through vocoders) V.21 preamble NSF Service Negotiation to S.O. = Analog Fax
CSI DIS BS/MSC/IW F
Synch TCP/IP-PPP-RLP
AT+CFG="" 0 AT+CVFQ? +CVFQ: 1,0 Max Rate Message
V.21 preamble NSF CSI
V.21 preamble
Relay CSI, DIS
DIS
CSI DIS
3 4 5 6
Figure 8.1.2-4. Call Set-Up as Voice Transitioning to Mobile Transmitting Fax. Voice Call Shown as Mobile-Terminated and Fax Call is Detected Using V.21 Preamble Detection.
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1
8.2
2
The following call flows illustrate various scenarios for Mobile Receiving Fax Calls. For Mobile Transmitting Fax Calls, the procedures are the same except that the functions of the IWF and the MT2 are reversed.
3 4
IWF and MT2 Procedures During Conversation State
TE2
MT2
BS/MSC/IW F
PSTN Fax
V.21 preamble NSF CSI DIS
Relay CSI, DIS
start CED tone V.21 preamble CSI DIS
V.21 preamble TSI V.21 preamble
Relay TSI, DCS
TSI
DCS for 4800 bps TCF @ 4800 bps
DCS for 4800 bps TCF @ 4800 bps
V.21 preamble CFR
Relay CFR
V.21 preamble CFR
image data @ 4800 bps
data message
image data @ 4800 bps
V.21 preamble
preamble message
V.21 preamble
MPS
Relay MPS
MPS
Relay MCF
V.21 preamble
V.21 preamble MCF
MCF image data @ 4800 bps
data message
image data @ 4800 bps
V.21 preamble
preamble message
V.21 preamble
EOP
Relay EOP
EOP
Relay MCF
V.21 preamble
V.21 preamble MCF
MCF V.21 preamble DCN
V.21 preamble CLOSE transport layer
DCN
5 6 7
Figure 8.2-1. Typical Mobile Receiving Fax Call Where the Initial Fax Training Rate from the Transmitting Fax Machine is Supported by the Air Interface
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1 2
TE2
MT2
BS/MSC/IW F
PSTN Fax
V.21 preamble TSI V.21 preamble
Relay TSI, DCS
TSI
DCS for 14400 bps TCF @ 14400 bps
DCS for 14400 bps TCF @ 14400 bps V.21 preamble FTT V.21 preamble CFR
Relay CFR
V.21 preamble TSI DCS for 12000 bps TCF @ 12000 bps
start blank lines @ 14400 bps V.21 preamble CFR
image data @ 14400 bps
data message
image data @ 12000 bps
V.21 preamble
preamble message
V.21 preamble
MPS
Relay MPS
MPS
Relay MCF
V.21 preamble
V.21 preamble MCF
MCF
3 4 5
Figure 8.2-2. Mobile Receiving Fax Call Where the Initial Fax Training Rate from the Transmitting Fax Machine is Not Supported by the Air Interface
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TE2
MT2
BS/MSC/IW F
PSTN Fax
V.21 preamble TSI V.21 preamble
Relay TSI, DCS
TSI
DCS for 9600 bps TCF @ 9600 bps
DCS for 9600 bps TCF @ 9600 bps
V.21 preamble FTT
Relay FTT
V.21 preamble FTT
V.21 preamble TSI
V.21 preamble TSI
DCS for 7200 bps DCS for 9600 bps
TCF @ 7200 bps
TCF @ 9600 bps
V.21 preamble V.21 preamble CFR
FTT Relay CFR V.21 preamble TSI DCS for 7200 bps TCF @ 7200 bps
start blank lines @ 7200 bps V.21 preamble CFR image data @ 7200 bps
data message
image data @ 7200 bps
V.21 preamble
preamble message
V.21 preamble
MPS
Relay MPS
MPS
3 4 5
Figure 8.2-3. Mobile Receiving Fax Call Where the Receiving Fax Machine Rejects the Initial Training Rate
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1 2
TE2
MT2
BS/MSC/IWF
PSTN Fax
V.21 preamble CFR
Relay CFR
V.21 preamble CFR
image data
V.21 preamble MPS
data message
image data
preamble message Relay MPS
V.21 preamble MPS
V.21 preamble MPS
V.21 preamble MPS
V.21 preamble MCF
V.21 preamble MPS Timer T13 expires (start preamble) V.21 preamble
Relay MCF (delayed OTA by channel)
MCF
data message
image data
V.21 preamble
preamble message
V.21 preamble
EOP
Relay EOP
EOP
V.21 preamble RTP
Relay RTP
V.21 preamble
image data
RTP V.21 preamble DCN
V.21 preamble CLOSE transport layer
DCN
3
4
Figure 8.2-4. Mobile Receiving Fax Call Illustrating the Use of Timer T13
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1 2
TE2
MT2
BS/MSC/IWF
PSTN Fax
V.21 preamble CFR
Relay CFR
V.21 preamble CFR
data message
image data @ 7200 bps
V.21 preamble MPS
preamble message Relay MPS
V.21 preamble MPS
V.21 preamble RTP
Relay RTP
V.21 preamble
image data @ 9600 bps
RTP V.21 preamble TSI
V.21 preamble TSI
DCS for 9600 bps DCS for 7200 bps
TCF @ 9600 bps
TCF @ 7200 bps
V.21 preamble FTT
Relay FTT
V.21 preamble TSI
V.21 preamble TSI
DCS for 7200 bps DCS for 7200 bps
TCF @ 7200 bps
TCF @ 7200 bps
V.21 preamble CFR
Relay CFR
V.21 preamble CFR
image data @ 7200 bps
V.21 preamble EOP
data message
image data @ 7200 bps
preamble message Relay EOP
V.21 preamble EOP
3 4 5
Figure 8.2-5. Mobile Receiving Fax Call with an RTP Response from the RX Fax Machine
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1 2
TE2
MT2
BS/MSC/IWF
PSTN Fax
V.21 preamble NSF CSI DIS (bit 9 =1)
Relay CSI, DIS
V.21 preamble CSI DIS (bit 9 =1)
V.21 preamble NSC CIG V.21 preamble CIG
Relay CIG, DTC
DTC
Relay TSI, DCS
V.21 preamble
DTC
V.21 preamble TSI DCS @ 4800 bps
TSI
TCF @ 4800 bps
DCS @ 4800 bps TCF @ 4800 bps
V.21 preamble V.21 preamble CFR
Relay CFR
CFR
image data @ 4800 bps
data message
image data @ 4800 bps
3 4 5
Figure 8.2-6. Mobile Receiving Fax Call Illustrating Polling (the TE2 has a document to send which the PSTN fax machine retrieves)
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TE2
MT2
BS/MSC/IWF
PSTN Fax
V.21 preamble TSI corrupted DCS for 4800 bps TCF @ 4800 bps
V.21 preamble TSI V.21 preamble
Relay TSI, DCS
TSI
DCS for 4800 bps TCF @ 4800 bps
DCS for 4800 bps TCF @ 4800 bps
V.21 preamble
V.21 preamble
corrupted CFR
TSI DCS for 4800 bps
V.21 preamble
TCF @ 4800 bps
TSI DCS for 4800 bps V.21 preamble
TCF @ 4800 bps
FTT
V.21 preamble CFR
Relay CFR
V.21 preamble TSI DCS for 2400 bps TCF @ 2400 bps
V.21 preamble CFR
start blank lines @ 4800 bps
image data @ 4800 bps
data message
image data @ 2400 bps
3 4 5
Figure 8.2-7. Mobile Receiving Fax Call with Corrupted HDLC Frames (corrupted DCS and CFR)
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1 2
TE2
MT2
BS/MSC/IWF
PSTN Fax V.21 preamble TSI
V.21 preamble
Relay TSI, DCS
TSI
DCS for 4800 bps TCF @ 4800 bps
DCS for 4800 bps TCF @ 4800 bps
V.21 preamble CFR
Relay CFR
V.21 preamble corrupted CFR
V.21 preamble TSI DCS for 4800 bps
start blank lines @ 4800 bps
TCF @ 4800 bps
V.21 preamble CFR
image data @ 4800 bps
data message
image data @ 4800 bps
V.21 preamble
preamble message
V.21 preamble
corrupted MPS
Relay MPS
MPS
V.21 preamble CRP
V.21 preamble
V.21 preamble
MPS
MPS
V.21 preamble corrupted MCF
V.21 preamble
V.21 preamble
MPS
MPS
V.21 preamble MCF
Relay MCF
V.21 preamble MCF
3 4 5 6
Figure 8.2-8. Mobile Receiving Fax Call with Corrupted HDLC frames and Fax CRP Option (corrupted CFR, MPS, and MCF)
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8-16
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9
TIMERS Timer
Definition
Value
Appears in
T1
Minimum amount of time that the Analog Fax Layer should remain silent over its analog interface before switching from V.21 demodulation to V.21 modulation.
200 msec
5, 5.1.3.1, 6, 6.2.3.1
T2
Minimum amount of time the RX Fax Layer should wait before transmitting TCF to the fax machine after the DCS has been sent.
75 msec
5.1.1.3, 6.2.1.3
T3
Maximum time permitted per scan line transmitted by the RX Fax Layer to the receiving fax machine.
1 second
5.1.2, 6.2.2
T4
Minimum amount of time that the RX Fax Layer should remain silent over its analog interface to the receiving fax machine after transmitting the end of page data.
200 msec
5.1.2, 6.2.2
T5
Minimum amount of time for sending V.21 preamble to a fax machine across an analog interface.
1 second
5, 6
T6
The page start timer indicates the time for which the RX Fax Layer should wait for the page data to arrive over the Um
3 seconds
5.1.1.3, 5.1.2, 5.1.3.2, 6.2.1.3, 6.2.2, 6.2.3.2
2.55 seconds for
5, 6
interface. If page start timer expires, the RX Fax Layer shall transmit blank scan lines to the receiving fax machine until page data reception begins over the Um interface. T7
The collision timer determines when transmission of a V.21
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message to a fax machine is permitted. The timer shall be reset to T734 and enabled upon reception of any final frame V.21 message from the local fax machine.
the MT2
1.55 seconds for the IWF
Transmission is permitted if the timer has not yet expired and inhibited otherwise. T8
Minimum amount of time for which the TX Fax Layer expects to hear a preamble over the analog interface to the transmitting fax machine before sending a Preamble Message over the Um
500 msec
5.2.3, 6.1.3
75 msec
6.1.1.1
interface. T9
After transmitting CED to the transmitting fax machine, the TX Fax Layer shall wait T9 before transmitting further signals (see T.30 4.3.3.2).
T10
Amount of time for which the Analog Fax Layer should wait before sending a repeated message to the fax machine if a response to the message has not been received.
3 seconds
5, 6
T11
The amount of time the Analog Fax Layer shall wait before directing the analog interface to release the call.
3 sec
5, 5.2.3.4, 6, 6.1.3.4
T12
The Analog Fax Layer shall close the transport layer and direct the analog interface to
50 sec
5, 6
34 T.30 specifies a 3.0s +/- 15% time-out between repeated V.21 messages for automatic mode
calls, and 4.5s +/- 15% for manual mode calls. This interval forms a transmission window during which the fax machine waits for responses. Setting collision timer at T7 ensures that transmission of V.21 messages to the fax machine do not collide with repeated V.21 messages from the fax machine.
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release the call when no messages are exchanged over the Um interface for more than T12. T13
This timer is started by the TX Fax Layer on receiving a total of three post page messages from the transmitting fax machine. Upon expiration of this timer, the TX Fax Layer shall start sending V.21 preamble to the transmitting fax machine if a response has not been sent. The TX Fax layer shall send V.21 preamble for a minimum of T5 and continue sending V.21 preamble until it has a response to send to the transmitting fax machine.
1
9-3
2.55 seconds for the MT2
1.55 seconds for the IWF
5.2.3, 6.1.3
C.S0017-007-A v1.0
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No text.
3
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1
10 DIS/DTC MODIFICATIONS
2
When the Analog Fax Layer receives a DIS or DTC message over the Um interface, it shall
3
modify the bits of the message as follows:
4
•
Bits 1 through 8 shall be set to zero35.
5
•
Bits 11 through 14 (rate bits) shall be modified according to Table 10-1. Table 10-1. Rate Bit Modifications
6
Bits 11,12,13,14 of original DIS/DTC
Bits 11, 12, 13, 14 of the modified DIS/DTC based on the maximum fax rate supported over the air (fax rates are in bits/second) 2400
4800
7200
9600
12000
14400
0000
*
*
*
*
*
*
0100
0000
*
*
*
*
*
1000
0000
0100
*
*
*
*
1100
0000
0100
*
*
*
*
N
0010
*
*
*
*
*
*
0110R
*
*
*
*
*
*
1010 N
*
*
*
*
*
*
1110
0000
0100
1100
1100
*
*
N
*
*
*
*
*
*
0101 R
*
*
*
*
*
*
N
*
*
*
*
*
*
1101
0000
0100
1100
1100
*
*
0011 N
*
*
*
*
*
*
0111
R
*
*
*
*
*
*
1011
N
*
*
*
*
*
*
1111 R
*
*
*
*
*
*
0001
1001
An asterix (*) indicates that the bits in the original DIS/DTC are to be left unchanged. Reserved (R) and unused bits (N) are left unchanged. In the event of ITU-T assigning new values to these bits, their values in this table may need to be updated. 7
•
Bits 21 through 23 (MSLT bits) shall be modified according to Table 10-2.
35 To prevent the use of Group 1 and Group 2 fax protocols.
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Table 10-2. MSLT Bit Modification
1
2
5
Bits 21, 22, 23 of the modified DIS/DTC
000
001
001
001
010
000
100
000
011
110
110
101
101
101
111
110
•
Bits 24 and higher shall be masked out unless the IWF and MT2 support the fax options advertised by these bits.
•
After modifying the message, the FCS value shall be recomputed according to 5.3.7 of T.30.
3 4
Bits 21, 22, 23 of the original DIS/DTC
7
In addition, if the MT2 or IWF does not support certain fax features, it shall modify the corresponding bits of the DIS or DTC messages received from the fax machine or the Um
8
interface.
6
9
10-2
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11 AT COMMAND PROCESSING
2
11.1 General Requirements
3
This section describes how the mobile station and IWF process the limited set of AT commands necessary for control of the analog fax service
4 5 6 7 8
10 11 12 13 14 15 16 17 18 19 20
The mobile station processes AT commands when the transport layer is in the ESTABLISHED state. When the transport layer is in the ESTABLISHED state the IWF reflects all AT commands (following the reception of the +CFG command) back over the Um interface to the mobile station, and the mobile can process the reflected AT commands. AT commands are classified as recognized or unrecognized. An AT command is considered recognized if it is defined for analog fax in this standard and complies with all requirements of the service in this standard. An unrecognized AT command is an AT command conforming with the syntax requirements of EIA/TIA-615 that is not defined for this service, or has a parameter value not mandated by this standard. When an AT command line is issued, the entity processing it issues a Command Response. A Command Response may consist of zero or more lines of Information Text, followed by a Result Code. The mobile station and the IWF shall observe the following rules when processing AT commands: 1.
21 22
When the transport layer enters the ESTABLISHED state, the mobile station and IWF shall perform the following: −
The mobile station shall send its stored configuration string, if any, to the IWF (see 11.4.3). If the mobile station has no stored configuration string, it shall send a null string. The mobile station shall use the AT+CFG SET parameter command to deliver the configuration string parameter to the IWF. The command line containing the AT+CFG command shall be terminated (i.e., no further AT commands can follow the AT+CFG command in the same command line).
−
The IWF should return an ERROR result code if it encounters errors processing the AT+CFG command.
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2.
The IWF shall respond to all received commands following the +CFG command with the appropriate response, via the Um interface.
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11.2 Basic AT Command Processing
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11.2.1 Action Commands
35
The mobile station and IWF shall support the action commands defined by EIA/TIA-602, and shown in Table 11.2.1-1.
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Table 11.2.1-1. Basic Action Commands
1
Command
Description
A
Enter the online state. See service specific processing for further details.
D
Causes the mobile station to transition from the command state to the online state. The is optional. The dial string may contain the following characters: Digits 0 to 9, *, #, A, B, C, and D. The dial string may contain the following dial modifiers: T
Tone dialing [ignore]
P
Pulse dialing [ignore]
,
Pause during dialing
W
Wait for dial tone
@
Wait for quiet answer
!
Hook flash
[$]
Wait for billing tone (for credit-card calls)
2
11.2.2 Basic Result Codes
3
The mobile station and IWF shall support the basic result codes of Table 11.2.2-1. The IWF shall encapsulate result codes (see Table 11.2.2-1) for transmission over the Um interface using the method defined in 11.3. The mobile station and IWF shall send the result codes in verbose mode as the default format. The mobile station may request the use of non-verbose (numeric) result codes by setting the V0 basic AT parameter (see EIA/TIA-602) in its stored configuration string (see 11.4.2).
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Table 11.2.2-1. Basic Result Codes
9
Source Numeric
Verbal
Description
0
OK
1
Reserved
2
RING
3
NO CARRIER
4
ERROR
6
NO DIALTONE
7
BUSY
8
NO ANSWER
Command executed.
MT2, IWF
Reserved
Reserved
Alerting signal received from network.
IWF
Unable to activate the service.
IWF
Command not recognized or could not be executed.
MT2, IWF
No dial tone detected within time-out period.
IWF
Reorder (Busy signal) received.
IWF
Five seconds of silence not detected after ring back when @ dial modifier is used.
IWF
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The ERROR result code shall be returned for all commands which do not comply with the syntax rules of 5.1 of EIA/TIA-615 or Section 5 of EIA/TIA-602.
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11.3 AT Command Set Extensions for Modem Control
2
The mobile station and IWF shall support the AT command set extensions for modem control as defined in [8] with the following exceptions:
3
•
Requirements describing AT command processing actions over the Rm interface are not applicable.
•
AT command result codes shall be sent in verbose mode as the default mode. Nonverbose mode is optional.
•
The procedures described in [8] for returning to on-line command state shall not be supported.
•
The procedures described in [8] for reporting dropped fax lines shall not be supported.
•
The procedures described in [8] for facsimile voice-request commands shall not be supported.
14
•
The IWF shall not perform the AT command reflection procedures described in [8].
15
•
Processing of cellular extensions to ANSI/TIA/EIA-617 shall be in accordance with [8] using only the command sequence listed in Tables 11.3-1
4 5 6 7 8 9 10 11 12 13
16
Table 11.3-1. IWF to Mobile Station Commands
17
Command Sequence
Hex Codes
Mobile Station Action
<0x19><0x61> Wait for Result Code before processing next <0x43> command.
IWF Action Issue when passing AT command response to mobile station.
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11.4 Cellular AT Command Processing
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The mobile station and the IWF shall support the AT command extensions and result codes for CDMA as listed below.
22
11.4.1 AT+CVF Command Processing
23
28
If the BS/MSC and mobile station are in the Conversation Substate with a connected service option other than analog fax, and the mobile station initiates service negotiation to connect a service configuration including an analog fax service option, the mobile station shall send the AT+CVF command to the IWF to indicate the fax calling station and any requirement for T.30 Phase A signaling. The AT+CVF command shall have the following format:
29
AT+CVF = ,
30
where:
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indicates the fax calling station. = 0, when the PSTN fax machine serves as the calling station. = 1, when the TE2 serves as the calling station.
6
is the T.30 Phase A signaling requirement. = 0, when T.30 Phase A signaling is not required. = 1, when T.30 Phase A signaling is required.
7
The AT+CVF command shall be preceded by the AT+CFG command.
8
11.4.2 AT+CVFQ? Command Processing
9
14
If the BS/MSC and mobile station are in the Conversation Substate with a connected service option other than analog fax, and the BS/MSC initiates service negotiation to connect a service configuration including an analog fax service option, the mobile station shall send the AT+CVFQ? query command to the IWF to determine the fax calling station and any requirement for T.30 Phase A signaling. The IWF response to the AT+CVFQ? command shall have the following format:
15
+CVFQ: ,
16
where:
17
indicates the fax calling station.
4 5
10 11 12 13
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= 0, when the PSTN fax machine serves as the calling station. = 1, when the TE2 serves as the calling station.
22
is the T.30 Phase A signaling requirement. = 0, when T.30 Phase A signaling is not required. = 1, when T.30 Phase A signaling is required.
23
The AT+CVFQ? command shall be preceded by the AT+CFG command.
24
11.4.3 AT+CFG Command Processing
25
The mobile station may send a stored configuration string to the IWF through the AT+CFG command. If the mobile station does not send a stored configuration string to the IWF, it shall send a null configuration string (AT+CFG=“”).
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11-4
