... is model M81190. I tried researching online and can't find the rate output spec for it. I'm using it in conjunction with a Raymarine course computer that has a built in rate gyro, and already have the SeaTalk to NMEA converter installed. This lets me read the NMEA sentences on my netbook using a terminal program and I can see heading info is being output on RS232 NMEA. I'm not sure if the heading output sentence is coming from the course computer or the fluxgate compass itself.

It's a fairly straightforward step to implement the RS232-RS422 converter and add the wiring, but running the wires and making up the connections will take several hours. I'm just waiting for a 40+F day to do it (it's 18-degrees F now, too cold to work on it).