ORIGINAL: alan0899
G'day Mate,
It's definitely #3, signal to negative, the two outside wires, either male or female. Easy.
Too add to the above. It is number 3 unless you are using a 6300 RX which only has 2 pins for the bind socket.
Also as an FYI--an MPI switch lets you, externally to the airplane, use the charging jack for the bind plug. with 6100, 6200, 7000 and 9000 R/Xs.
Regards,
Eric.