Home security system without a phone line?

I don't know anything about GeoArm put I have heard of Protect America. I would look at reviews of the companies online first before doing business with them. One the monitoring, both of those are good but gsm would be the most reliable because the panel and the cell unit (depending on the model used) has battery backups. The broadband is good but if your internet service is interrupted for any reason you are dead in the water. I suggest a system with both. At good alarm system for this would be a Ademco Vista 21ip with a GSM module added. The Vista 21ip has a internet communicator built into the board. And also be aware that almost all big companies are going to have you sign at least a three year contract for their service. So read the contract throughly.

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GeoArm has alternative universal communicators that can convert most existing security systems to take advantage of the broadband internet, Wifi, cellular or dual alarm communication paths. You may buy the equipment from us (lease to own it for free) or we also are glad to takeover the monitoring of equipment, if purchased elsewhere. http://www.geoarm.com/alarm-system-communicators.h...

You could use a DIY type that is wireless and local only. If you want notifications (whether to your cell phone or to a company) you still need a way for the system to do the contact. That will keep landlines in business longer.

Even battery power, the best you'll get is a loud noise that's not really going to scare anyone away and can be easily turned off. Your best bet is a big mean dog.