Transcript
ORDERING
SRM-8
SRM-8/*/+ Miniature Asynchronous/Synchronous Short Range Modem *
Specify: F for female 25-pin connector M for male 25-pin connector
+ Specify line interface: RJ-11 for RJ-11 jack RJ-45 for RJ-45 jack on a 2m / 6 ft cable RJ-45S for RJ-45 jack (Default is terminal block.)
Specifications are subject to change without prior notice.
607-100-01/99 1999 RAD Data Communications Ltd.
Miniature Async/Sync Short Range Modem
FEATURES
• • • • • • • • • •
Asynchronous or Synchronous Data rates up to 19.2 kbps V.54 diagnostics, including local and remote test Full or half duplex, point-to-point or multipoint Internal, external or receive clock
APPLICATION
DESCRIPTION • The SRM-8, Miniature Async/Sync Short Range Modem, is used for local data distribution, connecting full or half duplex sync/async V.24 digital devices over unconditioned 4-wire dedicated lines (twisted pair). SRM-8 operates at data rates up to 19.2 kbps, and at distances up to 17 km (10.5 miles), depending on wire gauge and data rate (see Table 1).
Transmission range up to 17 km (10 miles) Lightning protected No AC power required
Table 1. Approximate Range, Point-to-Point Data Rate kbps
Easy to install Miniature, lightweight
19 AWG (0.9 mm) km miles
24 AWG (0.5 mm) km miles
26 AWG (0.4 mm) km miles
19.2
11.0
6.5
5.0
3.0
3.5
2.0
9.6
14.5
9.0
6.5
4.0
4.5
2.5
4.8
15.0
9.0
6.5
4.0
5.0
3.0
2.4
16.0
10.0
7.0
4.2
5.0
3.0
1.2
17.0
10.5
7.5
4.5
5.5
3.4
• SRM-8 performs diagnostic loops in
•
•
•
compliance with the ITU V.54 standard. Two V.54 loops are available: analog loop (V.54 Loop 3) and remote digital loop (V.54 Loop 2). These loops are activated by either a three-position switch or by the DTE interface Circuit 141 (Pin 18) and Circuit 140 (Pin 21). A TEST LED lights when any of the diagnostic loops is ON. Asynchronous transmission is provided by internal conversion from async to sync, in compliance with ITU V.22 bis standard. Different async formats are switchselectable. In Synchronous mode, transmit timing can be provided by three alternative sources: − Internal oscillator − External clock − Loopback clock derived from the receive signal. The modem’s carrier can be strapped for either continuous operation (point-to-point application) or switched operation, controlled by the RTS signal (multipoint application).
• The low transmit level minimizes crosstalk
• •
onto adjacent circuits within the same cable. Data is transmitted and received at a balanced impedance, ensuring high immunity to circuit noise. Additionally, SRM-8 is coupled to the dedicated line through isolation transformers which, in conjunction with electronic circuitry, protect against AC or DC overvoltages. Innovative circuitry allows operation without a power supply, using ultra-low power from the standard RS-232 / V.24 data and control signals. Connection to the 4-wire line is via a five-screw terminal block. Optionally, the modems can be supplied with an RJ-11 jack, an RJ-45 plug on a 2m / 6 ft cable, or an RJ-45 jack (see Ordering).
SPECIFICATIONS • Data Rate (Async or Sync) 1.2, 2.4, 3.6, 4.8, 7.2, 9.6, 14.4, 19.2 kbps Selectable by a rotary switch
• Number of Data Bits (Async Mode) 8, 9, 10 or 11, including 1 start and 1 stop bit, with or without parity
• Frequency Allowance (Async Mode) Shortening of the stop bit on the receive end is selectable: − 12.5% allows a frequency difference between the async DTE and SRM-8 of -2.5% to +1.0% − 25% allows a frequency difference of -2.5% to +2.3%
• Transmission Line 4-wire unconditioned dedicated line (two twisted pairs)
• Transmission Mode Sync or async, full or half duplex
• Transmission Controls DCD (Circuit 109) turns ON after recognizing the receive signal from the line. CTS (Circuit 106) turns ON 0, 8 or 64 msec (selectable) after DTE raises RTS (Circuit 105). DSR (Circuit 107) is ON when the modem is powered and is in normal mode or analog loop state. DSR turns OFF when the modem is in digital loopback state. TEST Mode (Circuit 142) turns ON when the modem is in one of its diagnostic loops.
• Transmission Level -6 dBm
• Transmission Range Up to 17 km (10 miles) (see Table 1)
• Digital Interface EIA RS-232 / ITU V.24 integral 25-pin connector, choice of male or female
• Line Interface 5-screw (4-wire and ground) connector block with cable strain relief inside plastic cover. Optional interfaces (see Ordering): − RJ-11 jack, mounted directly − RJ-45 plug, on a 2m / 6 ft cable − RJ-45 jack, mounted directly
• Power
Declaration of Conformity
None required, uses ultra-low power from the V.24/RS-232 data and control signals. To ensure proper operation, the equipment connected to SRM-8 should provide at least one of the following control signals: RTS (Circuit 105) or DTR (Circuit 108/2). The typical power consumption drawn from DTE is 45 mW (at +6V signal level).
• Physical Length: Height: Width: Weight:
110 mm / 4.3 in 22 mm / 0.9 in 53 mm / 2.1 in 90 g / 3.3 oz
• Environment Temperature: 0-50°C / 32-122°F Humidity: up to 90% non-condensing
Mfr. Name: RAD Data Communications Ltd. Mfr. Address: 12 Hanechoshet St. Tel Aviv 69710 Israel declares that the product: Product Name:
SRM-8
Conforms to the following standard(s) or other normative document(s): EMC: EN 55022 (1994): Limits and methods of measurement of radio disturbance characteristics of information technology equipment. EN 50082-1 (1992): Electromagnetic compatibility Generic immunity standards for residential, commercial and light industry. Supplementary Information: The product herewith complies with the requirements of the EMC Directive 89/336/EEC. The product was tested in a typical configuration. Tel Aviv, November 26th 1995
Haim Karshen Quality Manager European Contact: RAD Data Communications GmbH, Lyoner Strasse 14, 60528 Frankfurt am Main, Germany
3.
INSTALLATION Caution. This is a delicate instrument. Be careful when setting jumpers or performing any actions within the product so that you do not break or shake any components.
• If using the terminal block: Connect each lead of the 4-wire line to the appropriate screw connector on the terminal block. • If using the RJ-11 or RJ-45 connector: Plug the cable into the RJ jack.
Installation of SRM-8 is simple and straightforward. Follow these steps: 1.
2.
Connect the 4-wire line to the modem line connector.
Open the unit by separating the two parts of the plastic cover – start at the cable end and firmly press the marked places on the sides. Strap the modem according to the Strapping Diagram (see Figure 3) and the Strap Selection Table (see Table 3).
Make the following connections between the local modem and the remote modem: • Connect the local XMT pair to the remote RCV pair. • Connect the local RCV pair to the remote XMT pair. Note: When operating in a noisy environment, use shielded cables, and connect the cable shield to "Ground". Ground is provided on the line connector (terminal block or RJ-11/45 connectors) for this purpose. If connecting to the RJ-11 and RJ-45 jack, refer to the Pin Assignment (see Figures 4 and 5).
Caution: Do not touch the transformer while connecting the terminal; it may brake under pressure.
-
3
3
*1'
;07
(;7
/('
ON 1 2 3 4 5 6
5&9
,17
&$5 6 6
S1(%) S2 S3 BIT S4 25 8 9 10 11 12.5 &17
5&9
',6 (1
$6<
21
6:,7&+
$6< /(1*7+
'/< PV
%$8' 5$7(6
0=19.2 1=14.4 2=9.6 3=7.2 4=4.8
Figure 4. RJ-11 Pin Assignment Figure 3. Strapping Diagram
Figure 5. RJ-45 Pin Assignment 4.
Close the unit by pressing the two halves of the cover together.
5.
Plug the modem directly into the 25-pin connector of the DTE or computer port. Fasten the screws on each side of the modem connector.
Sync Mode Set the baud rate, RTS/CTS delay (DLY), clock mode (RCV, INT, EXT) and the carrier (S4 of the dip switch) according to the application requirements (see Table 3).
Async Mode 1. Set the baud rate, RTS/CTS delay (DLY), ASY length (S1, S2, S3 of the dip switch) and carrier (S4 of the dip switch) according to the application requirements (see Tables 2 and 3). 2.
Strap the clock mode to ASY.
Table 2. Async Character Length Setting Start Bit
Data Bits
Parity
Stop Bit
No. of Bits
1
5
none
2
1
6
none
1, 1.5, 2
8 8
1
6
odd, even
1, 1.5, 2
9
1
7
none
1, 1.5, 2
9
1
7
odd, even
1, 1.5, 2
10
1
8
none
1, 1.5, 2
10
1
8
odd, even
1, 1.5, 2
11
Multidrop Mode - Sync or Async 1.
Make sure that the carrier is strapped to CNT (controlled carrier).
2.
Strap the RTS/CTS delay (DLY) as follows: − For data rates of 9.6 kbps and above: 8 msec or 64 msec − For data rates of 4.8 kbps and below: 64 msec only.
Table 3. Strap Selection Strap Identity Baud Rates
Function Selects data transmit rate
(kbps)
Possible Settings 0 - 19.2 1 - 14.4 2 - 9.6 3 - 7.2 4 - 4.8 5 - 3.6 6 - 2.4 7 - 1.2
9.6
RTS-CTS Delay
Selects RTS-CTS delay (msec)
0, 8 or 64
Clock/ Mode
Selects timing clock and async mode
ASYNC RECEIVE INTERNAL EXTERNAL
Async Format
Selects character length in async mode (see Table 2)
S2 OFF OFF ON ON
Factory Setting
8
S3 OFF ON OFF ON
INTERNAL No bits 8 9 10 11
10 bits
Selects the amount of stop bit shortening to be used in async mode
S1 ON – 25% OFF – 12.5%
12.5%
Carrier
Selects carrier constantly on or controlled by RTS
S4 ON– CONTROLLED OFF– CONSTANTLY ON
CONST ON.
ANA of DTE
Enables DTE control of analog loop (Pin 18)
S5 ON – ENABLE OFF – DISABLE
DISABLE
REM of DTE
Enables DTE control of remote digital loop (Pin 21)
S6 ON – ENABLE OFF – DISABLE
J1
Enables manual switch control of remote loop
CONNECT – ENABLE DISCONNECT – DISABLE
DISABLE ENABLE
OPERATION General Make sure that the loop switch is in the center position for normal operation, and the TEST LED is OFF. If the attached DTE does not use Pins 18 and 21, or if the cable between SRM-8 and the DTE does not contain those pins, set S5 and S6 of the dip switch to the DIS position (OFF).
Figure 1. Analog Loop This loop tests the local modem only. The XMT signal to the line is returned to the RCV signal.
Test Mode SRM-8 performs two of the V.54 test loops: analog loop (ANA) (V.54 Loop 3) and remote digital loop (REM) (V.54 Loop 2) (see Figures 1 and 2). Both loops are controlled by either a manual switch setting to ANA or REM, or by the DTE interface Pin 18 (ANA) and Pin 21 (REM). The TEST LED lights and Pin 25 (Circuit 142) is ON when the modem performs a diagnostic loop. Activation of both loops from the DTE interface (Pins 18 and 21) is controlled by S5 and S6 of the dip switch (see Table 3). Activation of the remote loop from the manual switch is controlled by Jumper J1 (see Table 3).
Figure 2. Remote Digital Loop This loop tests the local modem, the line and the remote modem. Note: To return to normal operation, move the switch to the center position, or if using the DTE interface, set Pins 18 and 21 to OFF. The TEST LED and Pin 25 will change to OFF.
