900 Family of Communication Interfaces

The 900 series of communications peripherals provide solutions for most two-way radio applications. A complete range of handsets, consoles and line interfaces allow an organisation to assemble various network configurations, with a minimum of fuss.

Omnitronics 900 Communication Interface

The 920 Remote Control Interface is an AUSTEL approved interface between handsets or consoles and two wire leased lines. Two models are available, the "T" version uses in-band tone signalling keying, while the D Version presents 12 volts to line for PTT.

An audio compressor ensures optimum levels for both transmit and receive. Up to three (3) handsets or consoles can plug into the 920 interface through 6 way US modular connectors.

A single plug pack can power the interface and its peripherals, with handsets and consoles operated up to 100 metres away.

An optional "Base Busy" sub-audible decoder gives local indication of the radio channel being occupied. The optional 920B operates in conjunction with the 925E fitted in the 925LKI. Multiple 920s can be paralleled at the two wire point.

A four wire version available for special installations using two leased lines or direct connection to bearers. This model is known as the 920T/4W and uses tone signalling.


The 935 Local Radio Interface allows direct connection of the 960 family of peripherals to a base station transceiver.

Communication applications where the operators are within 100 metres of the radio equipment are covered by this unit. Up to three peripherals can plug directly into the 935 with power derived from the radio. Radio level adjustment controls are provided to optimise audio quality to and from the handsets or consoles.


The 925 Line Keying Interface provides isolation and control from two-wire leased lines to radio base stations.

Two models are available, the "T" version which responds to tone keying and the "D" version, which responds to DC voltage to produce the PTT signal. The unit comes complete with plug and lead for the base station. Power for the 925 is derived from the base station supply. Base Busy Indication on the handset (or console), using sub-audible tones, is available using the 925E module for community base operation or in conjunction with the Omnitronics 950 Multiconsole Multi-radio System (Radio Management System). This works in conjunction with the 920RCI and 920B Base Busy Decoder. All versions are Austel approved (Permit No A90/19/0341).


The 934 Peripheral Interface enables the connection of Omnitronics 960 handsets, consoles or the 950 Radio Management System to 2 wire simplex (plus control line) devices such as the Omnitronics 9412 Audio Management Unit or 619E 4 wire 6 way Audio Bridge.

All '900' series equipment uses pre-terminated US modular plugs for quick connection. Often when the handsets or consoles need to be located some distance from the 920 or 935 interfaces, additional arrangements need to be made to terminate the wiring. The 930 EX Extension Kit consists of two wall mounted screw terminal blocks with 6 way US modular connectors and a pre-terminated cable for connection to the interface. The extension wiring can then be done with standard six core cable to screw terminals with sockets for the 900 series equipment. Up to 4 handsets can be wired in parallel in this way on a 'bus' type arrangement.

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