This Interface makes it possible to recive and transmitt using PSK, RTTY and all the other Digimodes using your Computer. I recommend using the Software Fldigi which runs under every OS and can additionally controll your TRX using CAT. So you can use three different methods for PTT: CAT, PTT-VOX and manual PTT with the PTT-Switch of the Interface. The Interface is really easy to build - it shouldn't take you more than a view hours.
The interface does galvanic separation by using two 1:5 NF-Transformators.