The interface is described in the Jul 2010 QST
The Classic Universal Interface has two isolation transformers and an opto isolator to run the PTT line from the computer serial port. I used a Radio Shack Gigaware USB to Serial Converter and this works well once you figure out the port the converter is using. It helps to look at the Device Manager on the computer. Then you have to tell the program you are using to use the correct pin on the serial port. An earlier and later ver of KH6TY Skip Teller interface using an audio derived VOX signal to trigger the PTT line which will also work.
All of the interface boards seem to be sold out on Skip Teller's site but FAR Circuits lists the VOX board from the June '09 QST Sound Card Interface for FM Transceivers.
|New DigiVox Interface Mar '11|