Group MMSI Number for S-B members

[Mr. Sandman]

I have to be honest, I have never used this feature of the radio. I
I would like to learn more about MMSI and DSC group operation and get it working properly on my radio. You have any good info on this? It sounds like a neat feature...It should be able to pass lat lon info from each others gps device, and from what I read, when I recieve a DCS call it the callers position will pop up on my chart plotter with a heading towards it (if he has it connect to his gps). This might be only for distress calls but I would think you could use it to covertly pass positions.

Lets start with a dumb question... what does MMSI stand for.