It depends on the security system and the VoIP (Voice over Internet Protocol) provider. The two most important considerations are the way that your VoIP security system communicates with the monitoring center, and how the VoIP service gets power.
Many security systems depend on standard telephone lines to connect to the monitoring center. Alarm system signals travel as a “sound” along copper wire, just like the buzzing noise of a fax machine or dial-up modem.
VOIP is more like a broadband connection; your voice is converted into digital data at your home and “streamed” over your Internet connection to the listener at the other end. Each VoIP provider uses slightly different technology to accomplish this, not all of which are compatible with every security system. The signal sent out by your VoIP service may not be recognized by the monitoring center as an alarm signal.
Compared to standard phone lines (often known as POTS, for Plain Old Telephone Service) VoIP has another critical consideration: backup power. When you lose electrical power to your home, by natural causes, or intentionally caused by intruders, any device without battery backup will be useless. Any professional security system will have its own dedicated battery backup for just such a situation, and standard phone lines work just fine without power, but most homes don’t have a similar backup for their digital phones or Internet connections.