VoIP Attracts Customers and Controversy

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.


9-1-1 SOS

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.


Fire Alarm Code Requirements

While the standards for transmission of security signals to off-site locations are primarily specified by industry groups, the standards for the transmission of fire alarms and their supervisory signals are subject to legal enforcement. NFPA 72, The National Fire Alarm Code, does not prohibit transmission means other than POTS (, but whatever method is chosen must have compliant operation.

A quick and dirty review of the requirements in the 2002 edition of NFPA 72 further emphasizes the criticality of alarm transmission reliability. Beginning with section 6.12, the code requires that any system transmitting signals to “continuously attended locations” provide not only alarm signals but trouble conditions to include fail-safe operation. This requires receipt of a signal when the power is lost or the phone carrier is inoperative.

If the alarm monitoring company has a DACT connected to the VoIP line, the requirements of Chapter 8 will still require compliance including, but not limited to, the following:

• Ability to seize and disconnect the line from incoming and outgoing calls.

• A second transmission medium that is automatically connected upon failure of the primary line. A list of seven methods is found in (A).

• Means to reset and retry the transmission attempts.

• Digital code or other means of verifying successful transmission.

• 24-hour (max.) interval testing.


VoIP equipment has not been universally tested or listed to verify that it complies with these requirements. NFPA 72 requires that “computer-aided alarm and supervisory signal-processing hardware be listed for the specific application.” In many local jurisdictions, this will require a fire alarm listing for the equipment.

Note that the requirements of NFPA 72 are only applicable when fire alarm systems are transmitted off-site.


Precautions to Take

The first step for those considering VoIP is to obtain the necessary information by simply asking hard questions. VoIP service providers and alarm central station monitoring services must be asked to demonstrate transmission of alarm conditions not only under normal circumstances, but also when

• there is a failure of the primary electrical power source; or

• the subscriber's VoIP line is in use.


Additionally, supervisory or trouble conditions must be demonstrated and documented upon loss of VoIP service or failure of VoIP conversion equipment, computers, cable service or other essential emergency communications transmitting components.

Potential subscribers should insist upon receiving direct affirmative responses to these concerns; observing the transmission of these conditions, and obtaining references of other users of the service who have alarm systems.


Industry Activity

The cable and phone service industry does not have the same level of strict standards enforcement that is present in the life safety industry. But some industry and non-governmental agencies are initiating activities that are intended to find solutions to these VoIP emergency communications concerns. Among these are the National Fire Protection Association and the Alarm Industry Communications Committee. The latter is a joint effort of the Security Industry Association, National Burglar and Fire Alarm Association and the Central Station Alarm Association.

These groups, and others, are beginning to work with the cable industry and VoIP provider representatives to propose solutions. The solutions will be multi-faceted to include activities that inform the public of VoIP operational issues; document industry steps to address these issues; provide direction and qualification standards for installers; and develop standards that can affect the engineered operation of VoIP infrastructure equipment. Among the first steps that must be taken: All the interested parties and groups must develop a framework to coordinate their efforts. Recently their cooperative efforts in establishing this framework have begun.

Progress in voice and Internet communication cannot and should not be restrained. New offerings in technology will bring new capabilities and, hopefully, reduced costs to users. But when new systems alter the infrastructure affecting our vital services, we must ensure that those essential services remain operational. Alarm systems protect the lives and property of millions of our family members, associates, employees and friends. VoIP service must be engineered so as not to jeopardize the essential emergency communications upon which public safety depends.


Ken Gentile is a senior consulting engineer for Rolf Jensen & Associates Inc. He is based in RJA's Houston , TX , office. Mr. Gentile may be reached by phone at 713-462-1840 or by e-mail at kgentile@rjagroup.com. To learn more about RJA, visit their Web site at www.rjainc.com.