SeaTalk to NMEA

[mm2187]

I am having issues getting a Raymarine ST40 to output boatspeed (SeaTalk) to an Standard Horizion WS150 (older but a nice unit) which accepts NMEA. I bought the PC/SeaTalk/NMEA Interface Box which is supposed to convert these two "codes" but when hooked up I am not getting the the corrected winspeed taking into account boatspeed.

I think my issue is I am not hooking up a wire because I do not know what it is supposed to be. The SeaTalk/power input from the ST40 is straitforward and the SeaTalk light inside the junction box lights up. The issue is that the WS150 insrument only has 1 NMEA input wire not two The output requires a positive and negative NMEA wires.

Does anyone know what the other wire is supposed to be. Is it a ground and I should connect it to the ground of the battery or is it something else.

Any input would be greatly appreciated.

[knuterikt]

Have a look at this document. page 9

http://www.standardhorizon.com/downl...lication%2Fpdf

Black cable is common ground (-)

[mm2187]

I understand that the black cable is common ground, both instruments power up and work with exception of calculating apparent wind. The Raymarine junction box/converter (from Raymarine to NMEA) depects that there needs to be two NMEA output cables, after the conversion from SeaTalk. I only have one cable (the green cable on page 9) not sure what the other input cable is supposed to be.

[hellosailor]

Call Raymarine, if the phone doesn't ring someone will be out of a job.

Odds are your "one" wire will be connected as the positive NMEA data lead, and you'll tie the equipment and power grounds to the "negative" data lead. There's a lot of confusion and flexibility and redundancy (is that redundant?) about NMEA /vs/ RS-232 versus differential and plain signaling.