When end users began shutting off their traditional phone service and replacing it with voice-over-IP service, it didn't take long before some people started having problems with their alarm systems, which typically are designed to share the customer's phone line. Four years or so later, the VoIP and alarm industries have had mixed results in finding solutions to these problems.
On the plus side, two of the nation's largest alarm installing companies -- ADT and Brinks Home Security -- have begun to endorse VoIP providers they say have taken the appropriate steps to address incompatibility issues. But those steps aren't sufficient to satisfy the National Burglar and Fire Alarm Association (NBFAA), which represents alarm installing companies and is pursuing legislation that would place additional requirements on all VoIP providers.
About 25 million alarm systems have been installed nationwide, according to Gordon Hope, general manager of Alarmnet, a unit of security manufacturer Honeywell. Comcast, which uses VoIP for the Digital Voice service that the company offers over its cable network infrastructure, estimates that 25% of Digital Voice customers have alarm systems. Potential incompatibilities between VoIP and alarm systems are fourfold.
One issue is that, unlike traditional phone service, which is powered through the central office, VoIP relies on premises-based power, which means that a customer could be without security during a power outage. Some VoIP providers, including some of the cable companies, provide battery backup -- although ADT, which has approved 25 VoIP providers for use with its alarm systems, doesn't require it. As ADT group director of strategy and business development Jason Nordin explained, "We have them certify that they have disaster recovery plans that address outages that are similar to landline phone service in their geographic region."
Another issue is that most alarm systems need to be rewired in order to work properly when traditional phone service is shut off in favor of VoIP. Alarm systems use a specialized phone jack, known as an RJ31X, which must be installed near the point where voice service enters the residence. With traditional phone service, that point is typically in the basement or back of the house. But cable modem service typically originates near the living room or family room television, while DSL originates near an office computer. If the RJ31X jack is not repositioned, Hope explained, a burglar could defeat the alarm system by taking a phone off the hook. In that scenario, he said, "The alarm panel would see a busy circuit and couldn't get a dial tone."
ADT requires its approved VoIP providers to rewire customers' homes as needed if they have alarm systems. Brinks Security, which has approved VoIP from Comcast for use with its systems, also has that requirement.
A third concern is that some VoIP services may not reliably transmit all alarm communication formats, which are used to send alarm signals to a central monitoring station and to remotely download changes to alarm system settings. Alarm industry communications formats are based on touch-tone, analog modem and other analog communication methods--and some of these may perform sporadically when used with VoIP, said Hope. He hastens to add that digital modem manufacturers have made some inroads in addressing this concern. But, he said, "It's still not what I would consider POTS line quality and you still may not be assured that the message will get there as cleanly as necessary."
But Nordin insists that ADT's alarm systems communicate reliably with approved VoIP providers, which include cable operators Cox, Comcast, Cablevision and Time Warner, among others. Nordin attributes the reliable performance to the fact that ADT only approves providers that operate their own IP networks. "The architecture of such systems are close in nature to the PSTN and the problem of packet loss or lost signals is simply lower with networks that are managed end to end versus going over the public Internet," Nordin said. ADT has not approved Vonage or AT&T's CallVantage VoIP service because both rely on the public Internet, he added.