The AIOB and AIOC both use unbalanced audio, utilizing a shared ground.

In some cases, a radio might utilize balanced audio. This means that there is a positive and negative audio input and/or output, instead of a “hot” and “ground” side like on most radios.

These types of systems can in some cases be directly interfaced with an AIOB, however audio levels may be low or distorted, and ground loops may occur.

A balanced to unbalanced transformer is the preferred method to overcome this challenge. More specifically stereo balanced to unbalanced line converters.

Stereo converters are preferred as the “left” channel can be used for the microphone input, while the “right” channel can be used for the speaker output.

One such affordable product is the SSM2141 Balanced XLR Input to Unbalanced Single Ended Output Board – available on Amazon for $35 at the time of writing. Similar adapters should work, and matching its input voltage with the voltage of your radio makes interfacing simple.