Connect GPS
There is a connection (possibly a cable is attached) where an external speaker, and the GPS NMEA leads are connected. Forget USB! Your GPS should have NMEA connections as well. On your radio the data in is the 'green' wire. Connect this to the data "OUT" of the GPS. Connect the brown wire from the radio to the BLACK (ground) of the GPS. Your radio does not have NMEA out, so it does not have a data out wire. If you can tell me the model of GPS you are using I can be more specific on those connections as well (if you can't find it your self). You need to study the items involved with using DSC, as it is more than just connecting a GPS to the radio.The black, and orange wires from the radio are the external speaker '-', and '+' leads (wires).