"David O" wrote in message
...


The manual for my Raymarine Ray54 VHF Radio says the radio accepts
NEMA 0183 (v1.5) data from a GPS device to provide Lat and Long info
for DCS distress calls. The manual shows the connections as:

GPS NEMA Out + to radio NEMA In + (yellow wire)
GPS NEMA Out - to radio NEMA In - (green wire).

The manual for my Garmin 178C GPS, however, shows the connections to a
DCS VHF radio as:

GPS Port 2 Data In to radio TX+
GPS Port 2 Data Out to radio RX+
GPS Ground to radio Ground

Apparently, the Ray54 doesn't send NEMA data back to the GPS so the
GPS "Port 2 Data In" connection should be left unconnected. My best
guess for the remaining connections is that the GPS "Port 2 Data Out"
should go to the radio's "NEMA In +" and that the GPS Ground should go
to the radio's "NEMA In -". Can anyone confirm this?

That is correct. See my web page about NMEA connections:
http://www.shipmodul.com/en/connections.html
Your case is a typical case of Single-Ended talker to Differential Lister
(Fig. 4).

Meindert