How does the TRX-SDR switch work?

The Audio Switch board is controlled by the TRX PTT signal coming from the TRX. Consequently, the Audio Switch controls the audio paths and the ANT Switch. TRX-SDR Switch Instruction Manual v.1.7.2 www.active-antenna.eu ©LZ1AQ Oct.2020

What is the output connector of TRX PTT?

11 There is an output connector J5 for control of external relays synchronized with TRX PTT state (Fig.7). The maximal current from J5 is 200 mA. Several low power relays can be connected there.

Why is TRX audio selected during transmission?

During transmission, the TRX audio is always selected, thus avoiding the effects of the audio delay from the SDR. The delay, with which the SDR audio is switched back, after the transmitting stops, can be regulated. This is important, since this delay depends on the specific SDR software and hardware being used.

What is iridium push-to-talk (PTT)?

With Iridium Push-To-Talk (PTT), group communications are enhanced globally with Iridium’s truly global, low-latency network. Interoperate with your traditional land-mobile-radios (LMRs) and enable rapid coordination with your team like never before.