1) VOIP requires continuous power to run. This means that if there is a power outage or, for some reason, there is complete power loss, you would not be able to use your phone, and your alarm system would be out of commission.
2) Alarm systems must have a precise and consistent frequency for their signals to communicate effectively. Because VIOP uses the internet to mimic phone lines, it is prone to losing data packets, frequency shifts, and data errors. These data loss and data error issues can interfere with the system's ability to communicate with the monitoring station. This issue can be life-threatening when an alarm system is not correctly sending fire, burglary, panic, or medical emergency signals.
3) For the VOIP phone service to work over the internet, the audible analog dialogue is converted to digital data and then compressed. Once the data is received, it is decompressed and re-interpreted. The decompression process can cause alarm signals to be lost or altered. On a phone call, when this occurs, it is slightly garbled or cutting in and out. In alarms, however, losing just one digit of the communication can make the entire signal unintelligible.
4) Even if your alarm system sends signals perfectly over a VOIP phone line during testing. The connection is still susceptible to issues from increased internet traffic, internet hops, lag time, and other concerns which can garble the connection, drop signals, and result in a loss of communication to your security system.
5) VOIP phone systems are more prone to user error. If someone were to unplug the cable that connects to internet service accidentally, your whole alarm system would immediately be down.