ComTekk - Tone Remote Console Software

Computer-aided Dispatch:

Interfacing a computer (PC) to radio transceiver

Method 1: Serial/USB Control

In this method, the radio must be located very near the computer, typically not more than 25' or 10 meters away. PTT (push-to-talk) is controlled via the computer's serial port, or with a USB to serial adaptor. The DTR or RTS pin is used to control an extermal relay, provided by a standard sound card interface box. TX and RX audio are either fed through or switched, depending on the interface type. At a minimum, isolation transformers should always be used to protect computer equipment from RF or high voltages on the audio lines.

Serial Control Simplified Schematic Diagram:

Method 2: EIA Tone Remote Control

This is a common method when controlling radio equipment located some distance from the operating position, and works with either a 2-wire or 4-wire twisted-pair line, such as a telephone line or CAT5 cable.

A tone control panel installed near the radio provides the interface from the line to the transceiver. Two or more operating positions may share the same line. Tone control is the legacy method used in most 911 dispatch centers. Newer installations are using voice-over-IP (VoIP) or radio-over-IP (RoIP) via ethernet, or in some cases over the Internet.

The first drawing below illustrates a simple method for connecting to an existing tone-controlled radio system. The second drawing gives a more detailed schematic.

Tone-remote console wiring

Tone Remote Control Simplified Schematic Diagram:

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Computer-aided Dispatch:

Interfacing a computer (PC) to radio transceiver