NMEA IN and OUT
Dwayne, all you need is a GPS with a NMEA OUT so you can connect it to your NMEA IN at your VHF. We have a Uniden UM525 with DSC (Digital Selective Calling)and we connected it to our Garmin's NMEA OUT, one wire for positive and the other for negative (ground). These connect to the corresponding (NMEA IN) pos. and neg. on your Uniden VHF. Once connected the GPS will send date, heading,speed lat.and lon., to your VHF to be used in case of an emergency DISTRESS.If you want to communicate with other boats, etc . for direct conversation then you should assign your own MMSI (Maritime Mobile Service Indentity), you can do this right on your Uniden VHF. If you make this number available to your friends,etc. and they give you their MMSI, then you can contact each other's boat directly. In the attached photo you should be able to see the date, heading, speed, lat., lon. on the screen. This is obtained from the Garmin GPS.Hope this helpsRich