Nearly finished

Here we have the back of the case, showing the data andĀ USB leads.


Left Is the delay circuit and opto-isolated PTT switch, I have also added a DC blocking capacitor, which does not appear in the circuit diagram. This is to stop the PTT line voltage triggering the VOX.

A Case and input !

The case is getting there, a switch to inhibit the PTT, Green LED to show power for the USB and a red LED to show that the interface is in PTT mode.


Left is pre-sets to control the volume in and out. It also has a common mode choke to protect the USB, which is a new addition to the circuit. Centre is the Audio isolation and VOX. Right is the start of a delay circuit.