[CA] [CA11] A78 Integrated with ST1 Network

[PJE56]

I'm help a friend out. He has a A78 MFD (E70202), an i40 bi-data and ST4000+ wheel pilot. I figured that a ST 1 cable can connect the i40 to the ST4000+ and then a ST1 - to NG converter can be connected to the ST4000. The A78 then connects into the converter with an NG spur cable.

The issue I am concerned about is power. The ST4000+ docs states that the direct connected 12VDC should be used and not power from the ST1 network; I understand that and it's fine. I will have the i40 direct power disconnected. I read in a thread here about a similar integration, that the power from the ST1 network should not be passed to the converter and the NG network. The suggestion was to cut the red wire on the ST1 converter cable. Is this the recommend solution or was this just because of the number of devices on the ST1 network? (This will only have 2 on the ST1).

My other question is if the A78 has the power cable connected will it power the ST ng bus? Or will additional 12vdc tap be required for the ng bus?

Thanks in advance.

Paul