phone operation

I just got an 01 SLK320 . . .LOVE IT!
How does the built in phone work? Do you have to subscribe thru MB??

Your profile didn't say where you are located but your english seems OK so lets assume you are in the U.S. First check to see who the provider is in your area for that phone (CDMA, GSM, etc..) and if they'll activate old phones, most won't since they don't meet federal guidelines for E911. If they will activate it, you are done. If not consider the mlkbox that allows you to use a non-MB handsets that are newer and meet the E911 guidelines.

Thanks. I'm in the US & currently have a cell phone. I'll ck with them. THe book talks about a card, but no card came with it.