While NMEA 2000 has become widely adopted across the marine industry, many legacy and commercial systems still rely on the older and very well proven NMEA 0183 data interfacing standard.
Remember this is a serial based protocol with operation at 4800 or 38400 baud – so slow speed sequential data based on a talker-listener protocol. Typically instrument and GPS systems run at 4800 baud but AIS requires a 38400 baud connection for the larger amount of data required. You can mix data together using a specialist and dedicated device called a multiplexer (like our WLN30) where multiple channels of NMEA 0183 information are combines and output as a single connection. Ultimately, however, bandwith is limited by the connection speed.
Many recreational boaters want to utilise navigation software on a PC. There’s free programs like Open CPN or more advanced systems like TimeZero (TZ). Modern PC’s don’t have old fashioned 9 pin D type serial connections so to connect to a boat system you need a USB-NMEA adaptor. Systems like TZ can support multiple connections so you could have one adaptor dedicated to the AIS (38400 baud) and another for GPS data (4800 baud) without the need for a multiplexer. When Digital Yacht’s USB-NMEA adaptor connects to a PC it creates a “virtual COM port” which mimics the older serial format for the application to utilise.
Even with modern NMEA 2000 systems, there’s often a NMEA 0183 output on the rear connections of a MFD and this older, simpler data is actually a lot easier to work with than NMEA 2000 for application developers. In general, apps can’t read native NMEA 2000 data so use devices like our iKonvert USB to convert NMEA 2000 data to NMEA 0183 over a USB connection.
The USB-NMEA adaptor is bi-directional so it can both send data to a PC and receive data (for instance autopilot information) from the application. Digital Yacht also offer a free NMEA reader program which can help with diagnosing interfacing issues or corruption.
In summary, the USB-NMEA adaptor is a great, low cost choice for getting GPS, AIS or instrument NMEA 0183 format data into a PC or MAC and a brilliant way of transforming an old laptop into a full function navigation device. You can get them HERE
