I would not use it for any alarm system. Just get the alarm CO to add a cellular communicator. All the ATAs seem to be less reliable for faxing than a POTS line. For healthcare, we still order POTS for fax machines.
I may have read magicJack doesn't recommend using their product with an alarm system or fax. When I was in healthcare telecom until recently, faxing was a very frequent requirement. As typical, many service calls from machines that were connected to ATAs having trouble with faxes. Not so many with those still connected to analog ports on the PBX.
I tried a magic jack years ago when they were new, and I was underwhelmed. Didn't provide disconnect supervision back then. Has that changed?
Don't know. Ooma (current system) does provide it. If I recall correctly, most if not all cable company's ATAs (typically Arris) don't provide disconnect supervision either. Had a few PBXs in the past where every month or so I'd have to pull a bridging clip on one of two lines that got stuck together. Probably on an after hours phone call where the caller chose an off site option. For my home use disconnect supervision isn't a requirement.
Yes, I had the first generation magicJack. I've heard the latest is at least acceptable. For the price and how often I use the home phone it's worth considering IMO, especially based on experiences I see here.
