--- title: "Standards and Protocols" description: "NMEA, Seatalk, SAE and other marine networking standards." --- ### Marine Industry Standards -

[IEC61162](https://en.wikipedia.org/wiki/IEC_61162) - International Electrotechnical Commission standards, partly wrapping NMEA standards (IEC 61162-1 is NMEA0183 and IEC 61162-3 is NMEA2000). -

[NMEA0183](https://en.wikipedia.org/wiki/NMEA_0183) - RS-422 based wiring layer with proprietary information protocol. -

[NMEA2000](https://en.wikipedia.org/wiki/NMEA_2000) - CAN Bus based wiring with proprietary information protocol. Also known as N2K. Open source reverse engineered documentation by

[canboat](https://canboat.github.io/canboat/canboat.html). - [NMEA OneNet](https://www.nmea.org/nmea-onenet.html) - IPv6 Ethernet based wiring with proprietary information protocol, using M12 and RJ45 connectors. - [NMEA over IP](https://opencpn.org/wiki/dokuwiki/doku.php?id=opencpn:manual_basic:set_options:connections:advanced) - Informal standard (with a formal IANA port assigned, `10110`) using TCP or UDP provided by several vendor and open source products, and consumed by Navionics, AngelNav, SavvyNavvy and more. ### Open Source - [SignalK](https://signalk.org/specification/1.7.0/doc/) - Open source JSON based standard using HTTP, OpenAPI and Websockets as transport layer and able to model NMEA0183 and NMEA2000 data. ### Vendor Proprietary - [ANT/ANT+](https://developer.garmin.com/ant-program/overview/) - Garmin protocol for low power devices, including linking watches to autopilots and chart plotters. Retirement announced by vendor in 2025, replacing with BLE. - **B&G Fastnet** - Proprietary serial bus network. No vendor documentation. Reverse engineered docs, C code and interface specs at

[B&G FastNet Notes](https://github.com/trlafleur/Fastnet) and [Oppedjik Blog](https://www.oppedijk.com/bandg/fastnet.html). - [Garmin BlueNet](https://www8.garmin.com/manuals/webhelp/GUID-C3D5DCE9-C0FF-4AC4-B759-D5B34E1EB78E/EN-US/GUID-A1161F2C-CEB3-4E87-9388-EE6F69DFD026.html) - Current Ethernet based netwoking, with proprietary connector. - [Garmin Marine Network](https://www.garmin.com/en-GB/c/networking-hardware/) - Previous generation of Ethernet networking, using RJ45 connectors. - **MicroNet** - Raymarine owned proprietary wireless protocol for instrument telemetry, originally known as *TackTick* before the original vendor acquired. Gateways available for two-way interfacing to regular Seatalk NG and NMEA 0183. - [Nexus](https://support.garmin.com/en-US/?productID=165155&tab=manuals) - Sensor protocol, acquired by Garmin and used for their wind instruments and depth transducer, with NMEA2000 bridge. - [RayNet](https://www.raymarine.com/en-gb/our-products/networking-and-accessories/raynet) - Raymarine's Ethernet implementation, using a proprietary connector. - [Seatalk 1](https://www.raymarine.com/en-us/our-products/networking-and-accessories/seatalk) - Raymarine proprietary daisy-chain combined data and power, ubiquitously deployed with ST60 instruments. - [Seatalk NG](https://www.raymarine.com/en-gb/our-products/networking-and-accessories/seatalk-ng-and-nmea-2000) - Raymarine's implementation of NMEA2000, compatible at data layer with a proprietary 6 pin connection to incorporate SeaTalk 1 data. - [SimNet](https://www.simrad-yachting.com/help--support/?contentTitle=Whats-the-difference-between-SimNet-and-NMEA2000&contentId=023_008-016) - Simrad variant of NMEA2000 with different connectors and supporting daisy chaining. ### Other Industry Standards on Boats -

[BLE](https://en.wikipedia.org/wiki/Bluetooth_Low_Energy) - *Bluetooth Low Energy*, a special form of Bluetooth for low power devices, on boats usually using the *Generic Attribute Profile* or GATT to exchange small quantities of data, like solar panel statistics or temperature. Uses the same 2.4Ghz frequency band as most WiFi. - Many SignalK plugins are available for BLE, including

[bt-sensors-plugin](https://github.com/naugehyde/bt-sensors-plugin-sk) for general device reading,

[eInk Labels](https://rhizomatics.github.io/signalk-einklabel-plugin/) to send boat data to an electronic shelf label, plus vendor specific plugins for

[Victron](https://github.com/stefanor/signalk-victron-ble),

[Bluetti](https://github.com/rhizomatics/signalk-bluetti-plugin) and others. - [CAN Bus](https://www.can-cia.org/can-knowledge) - *Control Area Network* specification and industry alliance, basis of J1939 and NMEA2000. - [LoRaWan](https://lora-alliance.org) - Long range wireless networking for IoT devices, including remote boat monitoring. - [ModBus](https://www.modbus.org/specifications) - Communication protocol for automation, used also in marine multiplexers, routers and control systems. Specifications and industry alliance. -

[MQTT](https://en.wikipedia.org/wiki/MQTT) - Lightweight publish/subscribe networking used extensively in home and industrial automation. Devices can publish data without being aware of what is reading the data, and clients can subscribe to data that was published before they started up. - Several SignalK plugins are available to expose boat data over MQTT, or pull MQTT data into SignalK, for example reading temperature sensors -

[SAE J1587/J1708](https://en.wikipedia.org/wiki/SAE_J1708) - Pair of older serial based engine networking standards, used by marine engines from 1990s and early 2000s. -

[SAE J1939](https://en.wikipedia.org/wiki/SAE_J1939) - CAN Bus standard, using Deutsch connectors, commonly used for engines and engine instruments, including Volvo Penta and Yanmar. - Several [vendors](#nmea-interfacing) provide interfaces to pull J1939 data onto the NMEA bus and there are standard NMEA 2000 PGNs for engine data, and related battery or fuel levels. -

[Shielded Twisted Pair Ethernet](https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair) - Computing industry standard, commonly used for radars and other high bandwidth marine applications. -

[TCP](https://en.wikipedia.org/wiki/Transmission_Control_Protocol) - Network protocol used for NMEA data distribution, to set up a session between a NMEA gateway and a client like OpenCPN or Navionics. Data is checked for receipt and retried if failed, so this is more reliable than UDP and also slower and more work for the gateway, hence commonly limited to how many clients can be supported at one time. -

[UDP](https://en.wikipedia.org/wiki/User_Datagram_Protocol) - Network protocol commonly used for NMEA data distribution, either passively (send out UDP packets to all clients that attach to a port) or actively ( forward on data to a list of listening client IP addresses/ports ), and either way as 'fire-and-forget'. Navionics, OpenCPN, AngelNav, SavvyNavvy and other apps will use this (or TCP) to subscribe to NMEA data. - [Zigbee](https://signalk.org/2025/signalk-zigbee-sensors/) - Common mesh network for sensors, alarms, switches and other home automation uses. Bi-directional (so for example, the device battery can be remotely read), designed for low power devices, and uses the same 2.4Ghz spectrum as Bluetooth and Wifi. Becoming more common on boats since home automation scale drives down the costs, and where [Home Assistant](https://www.home-assistant.io) is used in conjunction with SignalK.