OK, Had a look at the diagrams now. V5 of the Becker manual diagram 2.8.1 is how it should be wired. Moffrestorer has said the same
P9, Pin 2 has nothing to do with GPS if a parallel encoder is used and is your GPS data in
Use connector J8 pin2 for GPS/EN, if a parallel altimeter is connected.
J8, Pin 2 should be grounded to enable GPS
P9, Pin 1 goes to A1
P9, Pin 2 goes to A2
P9, Pin 3 goes to A4
P9, Pin 8 goes to RS232 data in from PAW(GPS)
P9, Pin 14 goes to B1
P9, Pin 15 goes to B2
P9, Pin 16 goes to B4
P9, Pin 17 goes to C1
P9, Pin 18 goes to C2
P9, Pin 19 goes to C4
P9, Pin 20 goes to D4
P9, Pin 11 goes to 10-33V DC supply
P9, Pin 12 goes to 10-33V DC supply
P9, Pin 13 goes to Ground
P9, Pin 25 goes to Ground