VHF Radio - GPS connection

[Sportfish1850]

Just bought a Cobra MR F 55 VHF radio. I have a Garmin GPSMAP 76S handheld GPS.

The radio came with a plug with read/black bare wires attached. The plug goes into a mini socket on the back of the unit. Instructions are to connect the red and black wires to the NMEA plug/output of a GPS unit as per the GPS manufacture's instructions.

The GPS instuctions say its possible to connect the GPS to a radio or other device using the Garmin power/data cable as per the radio manufacturers instructions.
The Garmin data cable has 4 leads, red (power) black (ground) and white and brown for data input and output.

So, now comes the confusion because neither company wants to give connection instructions for specific products out there but instead just says see the other manufacture's documentation.

So which wires from the GPS data cable (red, black, white, brown) connect to the Red and Black leads from the radio's NMEA input plug.

I'm assuming Red wire from the GPS data cable is the 12v hot wire, the black is for electrical ground. If so that leaves the white and brown wires to connect to the radio plug.....is it white to red and brown to black or visa-versa.

Or have I got it totally messed up ? Either way I'd like specific wiring info before I start experimenting and blow something inside either unit.

Have you done this or something similar ?

Any help would be appreciated.

[trollingforeyes]

Sportfish: Go to the Garmin web site and look up the manual online for your GPS. You should be able to find which color wires output data. Then compair that info to the radio instructions that show which color wires are for data in. You should be on the way.

[Sportfish1850]

Tried that already, it was my first thought. But thanks for the idea.

Problem is Garmin manual is not totally one-who-thinks-I-am-silly proof and I am no electrical whiz.

Garmin data wire has 4 leads RED (power +) BLACK (ground -) WHITE (input) and BROWN (output). Manual says attach the Red and Black to the 12 volt (+) and ground (-) of the 12v power system. No problem, can do.

The Cobra NMEA wired plug has RED and BLACK leads. Neither is specifically labelled input or output or ground but given the NMEA plug is for data transfer, I doubt either would be for electrical connection but ??.

I'm guessing that on the COBRA plug, RED is input and black is ground.
If so, the white from the garmin should go to red of the cobra and the black of both units joined together and put on the grounding plate. Note this is only a guess. BUT the black on the cobra could be output and then it might go to brown on the Garmin data wire... or the Cobra Red might be output and the Cobra black input.....and around and around I go.

There's the dilema.

Anyone made this same connection ? I'm just a bit afraid of running 12v + accidentally into my radio where it doesn't belong. I can smell those electrical components burning now.

[Sportfish1850]

Just to finish out this thread for anyone who finds themselves in this same dilemma and runs across this post, I wired the radio and Garmin power/data cable as follows.

2 Red leads from the Garmin cable and Radio power line to the 12v+ side.

3 Black leads from the Garmin cable, radio power line, AND radio NMEA plug to the 12v- ground.

Red lead from the radio NMEA plug to the brown (output) lead of the Garmin Data/Power cable.

White lead (input) on the Garmin Data/Power cable I cut off at the edge of the wire coating since its not used in this situation and didn't want it to dangle.

Turned on both units, power workds great, and after the GPS fired up and found sat signals, the Lat and Long appeared on the screen of my radio from the GPS input.

Remember to turn your GPS inferface onto NMEA rather than GARMIN in the menu settings to make sure your GPS will 'talk' to your radio.