Finally finished the Digi-Vox unit which is fully compatible with all CB radios. The whole unit is constructed in true "Home-brew" fashion, which is obvious to see from the pictures below.

The only deviations from the original schematic above, is firstly the use of a rotary switch to select when operating in either Digital or Voice modes, this will make life much easier with not having to plug and un-plug the microphone and speaker every time you wish to switch.

All connections can be permanently attached, with the microphone being plugged into the front of the Digi-Vox, and external speaker being plugged in via the rear 3.5mm jack socket. The unit doesn't even need to be power if operating in Voice only.

Secondly as I used a "Double Pole / Double throw" relay, I was able to add Send / Receive LEDs on the front panel for TX/RX operation.
 
Front Panel. Showing all the controls for operating. Easily toggle between Voice or Digital via the rotary selector switch.

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Rear Panel. Showing all input and output connections to your PC / Laptop sound card via the 3.5mm jack sockets. Also the main 6 pin aviation control socket to be connected to your CB radio.  A custom patch lead is required for the control socket as it carries all connections for the MIC, PTT, TX, RX and SPK. ( example to be posted soon ) Finally the last 3.5mm jack socket is used for an external speaker when operating in Voice Mode.
 
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Inside View. A typical copper clad, hand etched track work using a Dremel. The final result is not the neatest, but certainly the quickest. Plus without the use of etching with chemicals etc.

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