Koos - I don't understand why the connection to the remote wouldn't work. The Seatalk connection from the X-5 Course Computer supplies power to the S100 remote via SeaTalk. You can then power the P-70 using the S100 via Seatalk. Alternately, you can clip the Seatalk connector off the cable from the P-70 and hardwire it to one of the two Seatalk 3-terminal sets on the terminal board of the X-5 course computer.

It baffles me that Raymarine would make the Seatalk ng connection on the X-5 not have power included for the P-70 display, particularly for a single interface connection. I think the $150 you need to spend to power a Seatalk ng backbone is a rip off.