From James Miller G3RUH:
    
    Inject your modem TXaudio directly to the transmitter varactor in the
    SAT unit via J04 pin 2.
    
    1. Remove the main lid; remove the SAT unit lid.
    2. Locate J04 which is a 3 wire connector in the front left-hand corner.
    3. Unplug J04, and inject your audio on pin 2, ground on pin 1, using a
       screened cable.
    
    This is of course assuming you are using a G3RUH or K9NG 9600 baud FSK
    modems.  The receive side needs to come straight from the discriminator
    which I haven't had a chance to locate yet.  Perhaps if someone else
    has the necessary hook up information for the receive side, they could
    post it here.
    
    73,
    Todd
    N9MWB