The Garmin 17xgps (?) is a NMEA 2000
based unit and comes with everything needed to create a small N2000 network. Therefore the RM GPS won't work directly with the 4210. You can do all of this though, you'll just need to put in a Nmea
Multiplexer to connect the instruments to and then to the 4210. (The ST60s do put out a nmea
183, don't they?) Not too difficult. If you don't exceed the Garmin's inputs you don't need the multi. The 4210 can recieve the AIS
signal directly, but you have to configure the baud rate. And the 4210 will feed info to the AP.
I just did the same thing with Nexus instruments and a Simrad
AP, a SmartRadio AIS, lots of wiring
, but no problem.