"krj" wrote in message
.. .
Meindert,
The problem is that all the Raymarine Seatalk cables use red for yellow
for data, red for + volts, and the shield for - volts. Saves cost of s
third wire.
krj

I see. What you *can* do against HF interference is to run each cable 10
loops through a ferrite ring core.

Meindert