National Marine Electronics Association (NMEA)

A electronic and data specification ofr communication between marine electronic devices.  There are two standards I could find NMEA 0183 and NMEA 2001.

The Wiki pages lack history:

http://en.wikipedia.org/wiki/NMEA_0183

http://en.wikipedia.org/wiki/NMEA_2000

This is the official site:

http://www.nmea.org/

It cost over $300.00 to buy a copy of the standard.