NMEA help?

Getting Eagle Cuda sonar/gps with NMEA 0183  port.  Anybody using the NMEA stuff to upload / download maps and routes, etc.?  Where can I find plain English how-to help?

Thanks.

I got this answer:

Dear Mr. West,

Thank you for your inquiry.

The NMEA 0183 capability on your unit can be used to send GPS information to another device (i.e. GPS unit, autopilot, etc).  The cable needed to do this is the NDC-4 (119-31) and can be ordered through LEI Extras at www.lei-extras.com or by calling 1-800-324-0045.

Thank you for choosing Eagle.

Sincerely,

Eagle Electronics
12000 East Skelly Drive
Tulsa, OK 74128
1-800-324-1356
www.eaglesonar.com

LEI Accessories: Parts & Accessories 1-800-324-0045
Order online at www.lei-extras.com

Dwest,

We make high precision tiltmeters that use NMEA data strings to send tilt information to GPS units etc.  I know that someone here knows details related to NMEA standards and output strings that are compatible with different GPS units.  The main person I would want to speak to around here is out of the country right now at least until the beginning of August but if you have some specific information you need, I may be able to find an answer.

While I'm no expert the way I understand NMEA is that it isn't a way to download or upload maps and such, instead it is a communications protocol for different types of marine electronics.  For example in my motorized boat I have a fishfinder/gps combo unit that is connected to my VHF radio.  If I have an emergency I can broadcast an all ships emergency call and it will also send my gps coordinates, speed and course (from the gps) with that signal.  If somebody else sends an emergency signal the radio will put their location on the map page of my gps.

See:

http://www.gpsinformation.org/dale/nmea.htm

There's a link on that page which also discusses compatibility:

http://gpsinformation.net/main/nmea3.txt

And there is tons of info on the main page:

http://gpsinformation.net/

Thank you for the assist.  Probably going to get the Eagle cable and a compatible waterproof VHF radio and let it go at that.