Standard Radio Interface

This is a work in progress and is presented to encourage discussion and refinement in order to document a standard solution.

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Standard Radio Interface document


The Standard Radio Interface provides a universal connector for interfacing radios and accessories together. The first phase is to define the connector and connector pin out that to support physical interconnection. The next phase will define the electrical standards for each signal.

The benefit of a standard radio interface is the ability to swap radios of different make or model, without requiring a custom interface cable. This might be to replace a radio in a small repeater, or at a shelter where they are operating with the Standard User Interface.

The standard also allows a cross band repeater to be put on a different band, simply by swapping the radio. If a shelter has several voice channels in operation and they are causing interference, then one of the radios can be replaced easily by unplugging one and plugging in a radio for a different band. Now the link into the repeater might be on 6m or 1.35m.

What If My Radio Is Different

The majority of equipment can be interconnected quite easily simply by defining the physical interface. There is some equipment that will not provide the same electrical interface as defined for the standard interface. In cases where the equipment, a radio, TNC, or phone patch for example, does not support the standard interface, additions or modifications will be made to the equipment to meet the standard.

This may mean adding a circuit inside the radio to invert the PTT signal, or it may mean adding a small mini box to the outside of the radio, with interface circuit inside the box.

What If My Auxiliary Equipment Draws More Than 1.3Amps

The 1.3A current limit for the auxiliary power within the standard interface, will support most equipment such as TNCs, phone patches and repeater controllers. If the device requires more than 1.3A, it must be wired with it's own 12VDC power connection.


Packet PTT:

It has been identified that the PTT in the rear connector of some radios operates differently than the PTT on the microphone switch. The microphone PTT mutes the packet, while the packet PTT mutes the microphone. This will need to be addressed in the physical interface.