14.2. Fire and Burglary Systems
Many fire detection, sprinkler, and burglary alarm systems require the use of one or more POTS lines. This line is used to notify the monitoring company in the event of an alarm trip or a sprinkler head break. A modem inside the alarm system's CPU dials a computer at the monitoring station, and the alarm dispatcher's computer tells her information about the alarm trip.
These systems use an analog data modem that won't work reliably in a pure VoIP environment (see the earlier section, "Fax and Modems"). There are a few ways to overcome this problem. You could replace the system with a newer , Internet-aware system. Some alarm installers offer CPUs with Ethernet interfaces that can replace the modem for notification. But, if necessary, you may have to keep a POTS line (or two) around until you can upgrade.