M402 didnt receive the gps signal transmitted by garmin 72 via nmea 2.0

To connect your Garmin 741sx with your Raymarine ST 4000 using NMEA 183, you will need an NMEA 0183 interface cable to connect the two devices. Here are the steps to follow:

1. Obtain an NMEA 0183 interface cable that has the correct connectors for your Garmin 741sx and Raymarine ST 4000.
2. Connect one end of the NMEA 0183 interface cable to the NMEA output of your Garmin 741sx.
3. Connect the other end of the NMEA 0183 interface cable to the NMEA input of your Raymarine ST 4000.
4. Configure your Garmin 741sx to output NMEA 0183 data. Refer to your Garmin 741sx manual for instructions on how to configure NMEA output.
5. Configure your Raymarine ST 4000 to receive NMEA 0183 data. Refer to your Raymarine ST 4000 manual for instructions on how to configure NMEA input.
6. Once both devices are configured, the data from the Garmin 741sx should be transmitted to the Raymarine ST 4000 via the NMEA 0183 interface cable.

No. St series from Raymarine are made for digital depth only, not fish finding and do not talk nmea. The only way to get that Garmin of yours to see depth would be to go from an ST40 nmea out to that garmin nmea in. Or purchase a nmea 0183 smart sensor and hook it to the garmin.

I'm taking this as you want to send the gps information to your C80 not receive from the C80? If this is the case the brown wire on the garmin is the nmea data out +. The Black wire is considered nmea out neg (-) of the garmin. So hook the garmin brown to the white on the raymarine. Hook the black from the garmin to the green on the raymarine. That means you are outputting lat/long info to the raymarine from the garmin.

Free manual below. It's all in manual

https://buy.garmin.com/shop/store/manual.jsp?product=010-00309-00&cID=161&pID=214

USB cable and software found below.https://buy.garmin.com/shop/shop.do?pID=214&ra=true#accessoryTab

Yes, the NMEA- output (I think you lefy uot the "-" in your questoin), anyway, the NMEA - or NMEA negative or NMEA ref is hooked to battery supply ground.
Dont forget to program the Garmin to look for 48,000 baud data.

I connected my Garmin gpsmap76 to a Raymarine autopilot using the NEMA output from the GPS. The autopilot was also on the seatalk bus. It work fine. The GPS provided navigational guidance to the autopilot

yes, you need the NMEA out cord set for the E 80 and hook the output of the E series to the input on the power data cord on the Garmin - out to in

The unit receives signals from 3 (or more) satellites, and uses very sensitive timing to determine your distance from each of them. The unit does not transmit to the satellites, but only receives what they transmit... so it is a "receiver, only".

See here for the details of how a GPS works:
http://electronics.howstuffworks.com/gadgets/travel/gps.htm

Hope that helps you...

Okay
guys: book says:
PIN 1 (red) 10-40 volts DC
PIN 2 (black) Ground
PIN 3 (blue) NMEA out Shows this goes to Autopilot/NMEA devise and to RXD positive RXD negative goes to ground (black)
PIN 4 (brown) NMEA in Goes to GBR 21 Beacon Receiver to a blue wire, brown wire on thaat devise goes to PIN 3 and the negative goes to ground
PIN 5 (white) no connection
PIN 6 (Green) no connection
PIN 7 (yellow) goes to alarm low Shows going to negative terminal on alarm relay and positive terminal goes to PIN 1 (red)

All Greek to me, have fun

Seadrive Joe

Need more info:

Is your Garmin hooked up to your engine's computer via an NMEA 2000 data cable?

The gauge option will not appear in the menu if the GPS does not recognise the data coming from your engine. (If you turn on the GPS simulator, you should see the gauges on that screen.)

There are 3 possible reasons that the gauges do not appear in the menu:

1) improper wiring between engine and gauges.

2) GPS has not been set up to receive data in the GPS's NMEA setup menu.

3) Engine has not been set up to send NMEA data.

This is a relatively new feature that only works on newer engines that are NMEA 2000 capable, such as Volvo and Evinrude Etec.  The engines usually need an optional instrument package to make use of the NMEA 2000 system.

We're just scratching the surface here, please reply with any questions.