Audio Unit transfers voice signals through analog phone line generated by PSTN or VoIP adapter. There is possible to transfer audio from TRX directly to remote computer using SJPhone software.

You can hold up line grounding 'L' input by any Remote QTH relay or Open Collector Out1 at Control Unit. Grounding 'P' input or conecting the 'P' input to PTT bus you can simply change RX and TX mode, each with own audio level setting. All states are indicated by LEDs. This unit is powered from bus and the bus pass through the unit to be able for another unit.