The National Marine Electronics Association (NMEA; German National Association for Marine electronics) is an American association of electronics manufacturers and dealers of the shipping industry. The association was founded in 1957 and registered as a company in 1969. Its main objectives are the promotion of standards and technical developments in the marine electronics and technical training of its members.
The NMEA standard is a transmission standard in the maritime sector, which is available in different versions. Main application here is the exchange of navigational data between navigation instruments, such as GPS receiver, electronic speed log, depth sounder, AIS, ECDIS and other devices.
The first version of NMEA 0180 of 1980 defined a transmission at 1200 baud. These and the version 0182 (1982 appeared ) only have a historical significance.
NMEA 0183 (of 1983) operates at 4800 baud. For backward compatibility with older versions was abandoned partially, Version 0183-2.3 is not fully compatible to old devices. Since June 2012, the NMEA 0183 version 4.1 is current.
( " Listener " ) and devices that receive data, such as display devices - In the standard 0183, a distinction between devices that send data ( " talker " ), such as GPS. While a transmitter can transmit to multiple receivers, called a multiplexer is required for the use of multiple channels for common receiver. Data transfer is in small data units, the NMEA sentences ( " sentences" ). Each record must not exceed 80 characters.
The new NMEA -2000 standard is based on the CAN bus and is increasingly widespread. Devices with NMEA 0183 support but are still in the majority. Advantages of the new 2000 standards are the Plug and Play compatibility and 50 times higher data transmission rate. Furuno, Garmin, Lowrance and Maretron comply with the NMEA -2000 standard. Simrad uses a special NMEA -2000 version with slim plugs and calls the network " Simnet ". Raymarine calls his version " Seatalk ng ".
Related bus systems in the maritime sector
In addition to the standards of NMEA, there are other ways to connect different systems in shipping. For example, Raymarine has developed Seatalk own, NMEA 0183 similar system. This system has been deprecated. Another approach was developed by " Furuno NavNet ", here is a close relationship is given to 10Mbit Ethernet. Even CAN bus systems are on the market, such as as " Navico Corus ".