Adding a RAY70 AIS VHF

[Festinalente]

Hi again
I have E90w display interfaced with a radar, GPS and sounder with the help of a seatalk HD using rg45 cable.
Now I installed a VHF70 with GPS and AIS integrated. I want to interface it with my display as I can see the ships detected by the AIS. People at West Marine sold me a backbone (5) with two terminators, one power cable and two spur cables one between the backbone and the display and one between the backbone and the VHF.
Reading a lot on the web about this kind of installation there was one warning about power cable telling DO NOT put power cable if there is already power in the system. My question is should I put the power cable even if I already have a seatalk HD which I think is different from the std seatalk.
Thank for your help