FEATURES

• The SRM-8V, Async/Sync Short Range Modem, is used for local data distribution, connecting full or half duplex Sync/Async DTEs to computers over unconditioned 4-wire lines. SRM-8V operates at data rates up to 38.4 kbps, and at distances up to 19 km (11.7 miles), depending on wire gauge and data rate (see Table 1).

• SRM-8V 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 3-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 are ON.

• Asynchronous transmission is provided by internal conversion from Sync to Async, in compliance with the ITU V.22 bis standard. Different Async formats are switch-selectable.

• 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, or passing control signals end-to-end).

• DTE/DCE switch enables direct connection to DTE or DCE equipment, eliminating the necessity for a cross cable.

Note: When SW2 is set to DTE, the ANA switch (SW7-2) should be strapped to DIS.

• 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-8V is coupled to the line through isolation transformers which protect against AC or DC overvoltages.

• SRM-8V can operate without a power supply, by using ultra-low power from the standard V.24/RS-232 data and control signals. When the DTE cannot provide the power required, SRM-8V's power consumption can be significantly reduced by disabling the LEDs (strap-selectable).

• The line interface consists of two independent connectors: one is a 5-screw terminal block, the other is a selectable RJ-12 or RJ-45 connector (see Ordering).

• Five LED indicators are available to facilitate diagnostics: Test, Data Carrier Detect, Transmit Data, Request to Send, and Receive Data.

SPECIFICATIONS 

• Synchronous or Asynchronous
• Data rates up to 38.4 kbps
• V.54 diagnostics, including local and remote loopbacks
• Full or half duplex for multipoint or point-to-point
• Half duplex over 2-wires
• Internal, external or receive clock
• Controlled or continuous carrier
• DCE/DTE switches
• Isolation transformers
• No AC power required
• LED indicators
• Miniature, lightweight, easy to install

SRM-8V/*/+
Synchronous/Asynchronous Short Range Modem

ORDERING
 
SRM8V/F/RJ11
SRM8V/F/RJ45
SRM8V/M/RJ11
SRM8V/M/RJ45

APPLICATIONS