Connecting SmartPilot X-5 to Garmin 740

[njadventure]

Need some assistance from an electronics guru. I'm trying to connect an autopilot to a GPS using NMEA 0183. On the autopilot the inputs are labeled

+VE (In)
-VE (In)
+VE (Out)
-VE (Out)

On the GPS
Port 1 TX (Out)
Port 1 Rx (In)
Port 2 TX (Out)
Port 2 RX (In)

So my question is what gets connected to what?

Thanks
Bill

[Faster]

No expert, but.....

According to the 740 manual you've missed the black ground lead for NMEA 0183

To get GPS waypoints or tracks to your pilot, use Blue (port1 tx out) to the pilot's +ve(in), and the black NMEA ground to the pilot's -ve (in). If you can enable the GPS's port 2 you could probably use the designated port 2 TX out (gray) with the black ground.

There's a good diagram in the installation instructions.

[njadventure]

Thanks for the response. It took me a little while to think it through, but now I'm understanding the common ground piece.