RAD SRM-8 Sync/Async Short Range Modem 

Call us for Pre-sales and discount pricing

  301-924-7400 Support

RAD SRM-8 Sync/Async Short Range Modem    


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.
  • 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 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).
  • 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


  • 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
  • Transmission range up to 17 km (10 miles)
  • Lightning protected
  • No AC power required
  • Easy to install
  • Miniature, lightweight

Miniature Asynchronous/Synchronous Short Range Modem

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.)




RAD Products

For discount pricing on RAD Data Communications
email us at sales@data-connect.com
or call 301-924-7400