Seatalk

Seatalk is a family of proprietary maritime communications protocols developed by Raymarine.

The original seatalk protocol is a multiple-talker, multiple-listener broadcast 1 wire serial bus clocked at 4800 baud. Line coding is 1 start bit, 8 data bits, 1 command bit, and 1 stop bit. The bus was introduced in the 1980s, and is today a legacy bus. Classic instruments like the ST60 as well as ST2000 autopilots are known to still use it.

The specification for seatalk1 has not been made public, but a reverse engineered specification has been made by hobbyists.

Seatalk2 was a pre-standardization version of NMEA 2000 using square connectors.

Seatalk NG is an NMEA 2000 system with the exception of using a different connector than NMEA2000. This connector has 6 pins, to be able to transport the Seatalk1 bus alongside the NMEA 2000 data.

Seatalk HS is Raymarine's version of Ethernet but with non-standard connectors. With increased data rate, it support transmission of radar image, depth sounder data and similar.

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