Have had my SC1200 installed for about four weeks. I'll be returning it for two reasons: Range on DS10a's isn't more than about 25 feet and I need more. Also, telephone dialer sometimes connects to the telephone line and stays connected. There's no way to hang it up or disconnect, except to unplug from the wall, and keep it unplugged.
I did get it to work with my answering machine the first few times. I called the answering machine picked up, I put in my security code, and immediately could use the machine. Very cool being able to arm/disarm/listen to status, and turn on various lights etc using the cell phone.
Too bad about the range. I've tried every type of passive antenna on both DS10 and SC1200 but nothing will get enough range.