RAD SRM-6DC Asynchronous Multipoint Short Range Modem  

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RAD SRM-6DC Asynchronous Multipoint Short Range Modem     


The SRM-6DC, Asynchronous Short Range Modem, is used for local data distribution, connecting asynchronous DTEs to other DTE devices. SRM-6DC operates full or half duplex over 4-wire, or half duplex over 2-wire twisted pair lines, ensuring integrity of data transmission for distances up to 15 km (9.0 miles), depending on the gauge and data rate.
  • SRM-6DC complies with the RS-485 standard for multipoint environment. The modem's carrier can be strapped to be constantly on, or controlled by the RTS signal (Circuit 105). Operation with controlled carrier enables connection of SRM-6DC in multipoint configurations over 4 or 2-wires. Special circuitry for isolating inactive transmit pairs of wires, and two strap settings for high or low impedance of the receive circuit, enable SRM-6DC to work properly in multipoint configurations of up to 50 polled modems, without reduction of distance. The controlled carrier can also be used in applications that require passing a control signal end-to-end. (RTS on one SRM-6DC is passed to DCD on the other unit.) A unique circuit enables the user working in 2-wire half duplex to receive an echo from the modem even if DTEs used do not have an echo option.
  • Innovative circuitry allows SRM-6DC to operate without connection to the mains supply.


  • Asynchronous
  • Data rates up to 38.4 kbps
  • 4-wire full or half duplex
  • Complies with RS-485 standard (multipoint environment)
  • Operates in multipoint with up to 50 DTEs
  • Transmission range up to 15 km (9.0 miles)
  • Strain relief for line cable
  • No AC power required
  • Compact, lightweight, easy to install


Async Multipoint Short Range Modem

* Specify:
F for female 25-pin connector
M for male 25-pin connector
+ Specify line interface:
RJ11 for RJ-11 jack
RJ45 for RJ-45 plug on 2m / 6 ft cable
RJ45S for RJ-45 socket




RAD Products

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