ST290 GPS and NMEA issues

[Steve - Raymarine - Moderator]

You misunderstood the comment, you are not removing the power input to the S3 course computer and DPU you are removing the RED wire of the three wires of Seatalk interface (Red, Yellow and Black (bare)). Both devices will require their power 12 VDC feeds.

When adding a Seatalk to Seatalk NG converter to the backbone, you would remove the terminator in the Blue port of the existing converter and add a Seatalk NG backbone cable connecting the two converters together with the blue ports, then adding the terminator back into the last open blue port on the added converter.

You will also remove the splice between the Seatalk 2 5way and Seatalk to Seatalk NG converter. This is creating a data loop because this data is transferred through the DPU with it's connection to Seatalk.