Security directors and CSOs must keep informed of the impact of new technologies. Sometimes when a new technology is released before it's been thoroughly engineered, it causes a side effect that can jeopardize what were previously thought to be secure conditions and well-laid response plans. One such new development that should be of concern to the security professional is VoIP—voice over Internet protocol.
VoIP, by which voice signals are transmitted over a data network, attracts residential and business consumers with offers of extensive or unlimited local and long-distance calling minutes at a single monthly rate. Legislation requiring portability of telephone numbers has made it less inconvenient for consumers to switch to VoIP from POTS—plain old telephone service. The appeal of VoIP to vendors, telephone/DSL providers and other ISPs is that it can be packaged with cable or satellite television and Internet service to lock in all the communications accounts of residential and small business customers. VoIP has not, however, been without its controversies.
In a rush to bring the service to consumers, some developers overlooked emergency communication features that are taken for granted on POTS lines. Some VoIP services do not connect directly to 9-1-1, and some do not display the number and address of the caller to 9-1-1 dispatchers. The FCC is working with VoIP providers to address this problem technologically and by requiring that vendors fully disclose the service limitations to consumers before they sign up for VoIP service.
The 9-1-1 limitations aren't the only issue, however. If alarm system owners convert to VoIP, they may experience unreliable or failed transmission of alarm conditions to central stations.
Alarm Transmission Troubles
New subscribers to some VoIP services are often finding their alarm service inoperable or unreliable for one or more of the following reasons.
• Digital alarm communication transmitters (DACTs) and other alarm transmitters initiate tones designed for transmission over POTS. The specific tones intended for the central monitoring station receivers do not reliably propagate over some VoIP channels. Sometimes this transmission failure is the result of protocol conflicts, and other times it results from distortion of signals on the VoIP lines.
• Connection of VoIP service to the line side of an existing telephone service will prevent the line seizure that is required for an alarm transmitter to send its message. With this type of installation, there is no direct connection of the alarm system to the VoIP channel. Correcting this problem requires the installer to acknowledge the installation error and correct the wiring.
• The alarm panels are required to supervise the operability of the telephone line that connects the panel to its central monitoring station. With some forms of VoIP, the loss of an active transmission line can no longer be verified by the on-site equipment. Supervision of a loss of the connecting signal can only be performed by the central monitoring station. Providers should give subscribers some form of equivalent on-site supervision for loss of line.
• Depending upon the configuration and type of VoIP equipment installed, a loss of the electric utility power can make the VoIP connection inoperative. The secondary power source (battery back-up) in the alarm panel does not provide operating power to the VoIP equipment. A separate VoIP secondary/emergency source of power must be provided for any equipment essential for the operation of the VoIP channel.
The affects of VoIP conversion on alarm system owners can vary with each VoIP vendor or configuration. These consequences must be examined and addressed, because failed emergency, intrusion, or fire signal transmission could mean loss of life and property. Substantial exposure or liability issues could also affect the alarm system owner.