Leading by Design

Over 20 years experience in radio communications, security, telemetry, automation, mobile and fixed data systems.

SR123 RF Data Interface Radio Modem

SR123 RF data interface - Radio modemUniversal Com Link's SR123™ radio modem is the communication link to pull everything together.  The SR123™ is a digital RF data interface for use in M2M (machine to machine) applications.  This radio modem can be used as a standalone unit or as an integral part of a complete telemetry system. 

The unique radio interface of the SR123™ makes the modem compatible with all two-way radios, cell modems and other wireless forms of communication.

Read more about uses for the SR123™ on our Telemetry & Industrial Application Solutions page.


Highly compressed GPS data that allows every two minutes (settable) points compressed 6 to a buffer and multiple buffers can be sent in a single transmission saving radio air time.

Radio messages as well as BLACK-BOX data (which is one per second GPS points) are recorded to the 1Gig SD card. It can record data for five years under normal operations before wrap-around.

Any programming or settings can be changed remotely so there's no need to go to the modem to make changes. 

What is Machine to Machine

M2M communications consists of using a device (e.g., sensor, meter, etc.) to capture an "event" (e.g., temperature, inventory level, location, environment status, etc.), relayed through a network (e.g., wireless, wired or hybrid) to an application (software program), translating the captured event into meaningful information (e.g., there is a breach, pump not running, tank level too high, an accident has occurred, etc.)

Inputs / Outputs

SR123 Radio Modem14 digital inputs to monitor all kinds of vehicle activity, inputs can be defined to be low or high asserted and critical or nominal. Critical inputs report changes immediately. The inputs are protected from up to 60 volts DC.

6 digital outputs to perform any control operation. They consist of relay drivers that drive any 12-volt relay.

The modem monitors and passes the ignition signal to the radio. This feature allows the modem to control radio power by feeding it a simulated ignition and keep the radio on in the field to connect with the workers when the ignition is off.

The modem provides 5VDC to the serial port pin-9 to provide power for devices attached to the serial port.

The modem can be powered from the radio or directly from the vehicle battery with voltage protection of up to 30 volts DC.

Example of SR123 in a fixed application
Example of SR123 used in a fixed application
(click image to view larger)

Networking Capabilities

A unique feature of the SR123™ is that if a computer is connected to the serial port, it accepts it as another host on the network. In other word the base modem is just like the field modem with server connected to its serial port. This feature allows the network to exchange messages of any kind between the base server and computers connected to the field modem. Allowing text messages and other routing data to be exchanged between the server and remote field computer.

SR 123 Radio ModemAny other serial device may be connected to the serial port of the modem and be controlled by the server connected to the base modem.

The modem also allows a network to be built with two-wires alone for monitoring of fixed assets. The two-wire system allows power and data to be delivered to each modem.

Road Use Features
  • A speed control parameter reports whenever the vehicle is going over the assigned speed limit.
  • SR123™ tracks vehicle idle time - reporting the length of time the vehicle was idling and not moving.
  • A built-in soft odometer calculates mileage driven with less than 1% error compared to the odometer on the vehicle.
SR123 Radio Modem used in a mobile situation
Examples of SR123 used in a mobile application (click image to view larger)

SR121 ~ for Analog Applications

The SR121™ has all the same great features of the SR123™ but is designed for analog applications.

Industrial Tough

Housed in a rugged extruded aluminum box, the SR121™ and SR123™ are built for dependability and long life - designed to withstand the temperature fluctuations and heavy vibration of mobile operations. All solid state construction - no moving parts to fail. Add to that an operating temperature of -30° to +180°F and you are looking at one tough modem!

The SR123's small 4"w x 5.25"h x 1"d size means more room for other components in tight areas.

SR123 Features
  • 12 channel GPS receiver
  • MMC/SD socket storage interface
  • RS232 serial port
  • Two-way radio modem connection
  • Remote communication through serial, TCP/IP, two way radio, wifi, satellite, point to point/point to multi point
  • Remote control functionality - all programming can be done remotely
  • 14 digital input signals
  • input for ignition
  • 6 digital outputs
  • Data logging to SD card
  • 4 LED's - RUN, GPS, RX, TX
  • -30° to +180°F operating temp. - built-in sensor reports ambient temp. of modem
  • 300G shock tolerance
  • 3 year warranty - 5 year extended available
Field Proven Reliability

The SR123™ has been operational in vehicles and in rough industrial environments with NO failures in the field for 3+ years!

Our Solutions

Mobile & Fixed Products

We offer many products including:
 · Two Way Radios
 · AVL/GPS Tracking
 · Mobile DVR systems
 · Mobile computing platforms
 · Industrial computing platforms
 · Fleet Management systems
 · Telemetry systems
 · Dispatch Software & Hardware
 · Voice Recording/Logging
 · Radio over IP
 · Voice over IP
 · Automatic Passenger Counters

We have WiMAX & WiFi solutions

For use in:

  • Mobile Fleet Tracking
  • Water & Waste Management
  • Mining Operations
  • Oil & Gas
  • Agriculture
  • Energy & Power
  • Monitoring Stations

More Information

    Brochure - Fixed Application
    Brochure - Mobile Application
    Data Sheet

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      Fremont, OH 43420
      Office 567.202.0646
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