I contacted Garmin about this very issue. Here's what they told me, I
tried it and it works just fine.

The way to connect these units together is to join the brown (data
out)
from your 76 to the VHF NMEA in (+). The NMEA (-) wires need to be
tied
to the same ground as the 76 black wire. The NMEA out (+) will not be
used; neither will the data in on the 76. After you get the wiring
accomplished, you will also need to change a setting on the 76 so it
will communicate in the same language. To do this, press the menu
button twice to go to the main menu. From there select setup and then
tab over to interface. It should be set a Garmin, you'll want to
press
enter and then select the option NMEA. They should now be
communicating
freely.


Peter
a/v Now or Never!

On Apr 10, 1:16 pm, "Roger Long" wrote:
I hooked up the NEMA output from my Garmin GPSmap 76x to my Quest radio this
morning.

The radio has a NEMA in and NEMA out line and shows them connected to wires
of the same color for a GPS by the same company. A few pages later there is
a table for NEMA connetions to various brands of GPS.

Both fixed mount and portable Garmin's show the NEMA out line from the GPS
to be connected to the ata In" in line on the radio. The radio "Data Out"
line is indicated as connecting to "Black - Neg Ground". I therefore put a
wire from the ground block where the black negative lead from the GPS power
cord attaches and ran it to the Quest radio "Data Out" lead. I'm sure this
is what it said to do but it seems odd.

I haven't turned anything on yet so, if anyone can confirm that I did it
right or head off melting something, I would appreciate it.

Please: only if you know. I hate those post responses that start out, "I
haven't got a clue but here is what I guess."

--
Roger Long