[CA] [CA11] Integrating Garmin GPS into Seatalk 1 network

[Chuck - Raymarine - Moderator]

Mark,

It would not be recommended that the NMEA 0183 output of the S2 autopilot course computer be interfaced to the 74CV GPS/Chartplotter or a NMEA 0183 data loop may result. Should the 74CV GPS/Chartplotter have some control over which NMEA 0183 sentences will be received, then switching off all sentences except for those containing heading, rudder, and instrument data would be recommended. Alternatively, a programmable NMEA 0183 multiplexer (ex. Actisense NDC-4) may be installed between the autopilot course computer's NMEA 0183 output port and the 74CV GPS/Chartplotter's NMEA 0183 input port.

Please additionally note that the S2 feature two SeaTalk ports. One should be used to interface the instruments to the S2 and the other should be used to interfaced the autopilot control head alone to the S2. All three lead of the SeaTalk cable connecting the autopilot control head should be used, while only the data (yellow) and ground (shield) leads of the SeaTalk cable connecting the instruments should be used. When so interfaced, the autopilot may be used irrespective of the power state of the instruments. The additional separation may provide a degree of isolation should a device suffer a failure of its SeaTalk communications circuitry. When such SeaTalk failures occur, they may block communications within the entire SeaTalk bus.