NMEA 0183 and N2K
Broadly speaking NMEA comes in two different strains, the old NMEA 0183 (in various versions) and the more modern NMEA2000 (N2K). They are significantly different in the way they transmit data. However kit available to link the two makes the NMEA standard even more versatile and allows to stick to sensors already in place. There are various websites containing information for further reading on NMEA cabling and details i.a. by Actisense.
NMEA 0183 shows pros and cons compared to NMEA2000 or dedicated systems like Seatalk made by Raymarine. What we appreciate with NMEA 0183 are now low prices for NMEA 0183 gear, second hand devices available eg on ebay, and robust systems’ performance which comes at the prize of more thinking required to set-up these types of systems. The latter has become even more relevant through very low-cost IT options using Arduino or Raspberry open standard computing platforms
Differences between NMEA 0183 & NMEA2000 (N2K)
NMEA 0183 | N2K |
Fully open/non-proprietary standard | Fully open/non-proprietary standard |
One-way communication | Bi-directional |
Open to other systems like NK2 and proprietary systems via adapter | Open to other systems like NMEA 0183 and proprietary systems via adapter |
If one component/device fails, the others continue to work | If the bus fails there is a good chance the Nav system may come down completely |
Relatively slow | Fast |
Serial system, to be monitored with simple terminal program | CAN-Bus-type system, monitor with dedicated software |
More complex to set-up, one-to-one cableing necessary | Plug & Play technology, one bus cable |
Some compatibility issue between versions RS 232 and RS422 equivalent | |
Cheap & 2nd-hand units available | Pay market prices |
Little future development to be expected to include more devices | Continuous inclusion of more equipment under way like engine controls |
N2K is continuously expanded to include more devices like eg engine controls. Analogue/digital converters are available to include engine data like pressures, temperatures, tachymetre data, with non-specific kit available for virtually all analogue data to be converted. This is not to argue, that this is regarded a positive development for vessels putting to sea relying entirely on computerized displays.
Move on to who’s ‚talking‘ on board electronically