Tech Update From Technical Director Steve Spitzer
NMEA 2000 ®
Make sure you know what you’re buying
The National Marine Electronic Association’s NMEA 2000® is on fire and growing by leaps and bounds. NMEA 2000® is a very
robust and solid industry standard that allows boaters to use products from many different manufacturers on the same network.
NMEA 2000® is not a proprietary standard that was created by one manufacturer for just their products. Marine electronic and
electrical manufacturers, including computer companies, universities and the US Coast Guard Research and Development Cen-
ter, joined together as part of the NMEA 2000® Standards Committee to create an “open” network environment for the entire
marine industry to use. From its inception, NMEA 2000® was built as a “networked” protocol.
The foundation for NMEA 2000® is what’s called a Controller Area Network (CAN). CAN was invented by the auto industry and today is the commonly used commu- nication protocol in automobiles. CAN’s advantage is its built-in system for prior- itizing messages, thereby guaranteeing that the most critical message on the net- work will always get through to its destination, which is an essential component
3870-B Longview Drive Douglasville, GA 30135
for autopilots and other steering mechanisms. NMEA 2000® can provide complete command
and control capabilities.
If you have marine electronics on your boat, you most likely have a communications
protocol interface called NMEA 0183. This is an embedded language in marine electronics
that allows them to talk to each other. NMEA 0183 basically is a single-talker, multi-listener
one-way communication avenue. In other words, one device can talk while others listen.
There is no talking back and forth. Simplistically, a GPS can talk to a chartplotter or a radar.
While it is terrific for simpler applications, NMEA 0183 was never meant to be a “networked”
protocol. Here is a very simple illustration of the single-talker/multi-listener principle:
ILLUSTRATION 1 (SINGLE TALKER/MULTI LISTENER)
(Continued on page 47)
NMEA 2000®’s cable and connectors
are standardized. To be an NMEA 2000®
network, the cables and connectors must be
approved by NMEA. NMEA went to the factory automation industry to find the best
system available and developed the specifications from that industry. The goal was to
provide an extremely robust and proven
cable and connector system that would
have power and data in the same cable while minimizing noise interference on the
Look for
the Logo
To ensure your NMEA
2000® electronics operate properly, use
only NMEA 2000®-Certified products
and work with an NMEA 2000®-trained
dealer.
