I developed the printed circuit board shown to tie my dual Skyview system together and provide outputs to all the devices it covers. It is also my single point ground.

The 25 pin Dsubs go to the displays and contain all the serial, contact, gps, ADSB, Transponder, power and output wires that must be connected together. It uses two wires for Skyview power and ground. (Dsub connector pins are rated at 5 amps each).

The 9 pin Dsubs allow dedicated cables to each of the devices in the Skyview system:

Transponder
ADSB Receiver
GPS Antenna
Audio and Dimmer circuits
Spare Serial Port and all Contacts
Power in and contacts out. Power for the Skyviews, Transponder, ADSB Receiver, inputs from the aircraft, i.e., Autopilot disconnect, etc.

The two 36 pin connectors are all grounded to provide way too many common grounds. There are four tabs in the corners to connect the board to the aircraft ground.

There are solder points in most lands to pick up whatever I missed.

It is in my flying RV-10 and works well.

Circuit board
 

That is awesome Bruce.