The interface is finally finished, boxed and labelled. ready or portable use.
It was hard to fit it all in a small box. Might be time to re-think the design !. Version 3 coming soon !
Here we have the back of the case, showing the data and 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.
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.
Sound activated switch (VOX) is finished !
First part is done. This is two isolation transformers and the first part of the audio activated switch.
It is time to build a USB Data interface for portable use. Field days, SOTA and quick QRP trips etc. I am going to use my design, which can be found here : http://www.m0zpk.co.uk/soundcard-data-interface/
This is my work area.