DSL Internet connections can interfere with alarm system dial-out

Sunday, December 1, 2002

Most alarm systems cannot dial out when DSL service is connected in a home or small office. As alarm service providers and DSL Internet access providers are finding out – many times the hard way – DSL connections and home alarm systems are often incompatible.

How DSL works

DSL provides high-speed Internet access over the customer's existing copper telephone wires. A telephone company or an Internet service provider, like MSN or AOL, typically provides the service. Once activated, the DSL signal is "always on" and shares the same pair of copper wires as the voice band telephone service.

That causes the primary problem with DSL and alarm panels. The ever-present DSL signals can interfere with the alarm system's built-in modem, preventing the alarm panel from dialing out to the alarm company in the event of an emergency. The second conflict occurs if the alarm panel takes custody of the phone line, disrupting the DSL signal. This can be a serious issue if DSL is supporting video security or health monitoring equipment.

Who's to blame?

Because DSL service is often added long after the home or small office alarm system has been installed, alarm providers are often unaware of potential problems until it's too late.

The typical installation contract and/or service contract for ongoing alarm monitoring usually includes a lengthy disclaimer about the alarm's operation if DSL service is connected. When a home-owner signs the contract, he may not be aware of the potential conflict. Yet the alarm company will bear the brunt of the customer dissatisfaction if the alarm fails to report an emergency.

The phone companies and Internet service providers also place the responsibility for proper alarm operation on the alarm provider.

Unfortunately, while the alarm providers easily become the responsible party by default, they typically have no cost-effective solution, leaving home-owners frustrated and questioning the value of two competing services – the security of an alarm system or the convenience of faster Internet access.

The fix that often fails

One solution is to install a splitter at the home's main phone interface separating the DSL signal from the voice band. However, this is not always convenient for the homeowner who must be on-hand for a potentially expensive service visit from the installer. Alternately, instead of installing a splitter ahead of the alarm panel, some alarm installers use a standard filter for alarm panels that share the phone line with DSL. While this solution eliminates DSL interference on the phone line, it prevents the alarm panel from "seizing" the line in case it is cut or there is an emergency.

The better solution

Recently, a new DSL filter for alarm panels has been introduced that's easy to install and very effective. These new filters are designed to plug easily into the alarm panel's telephone connection and testing of the dial-out function takes just a few minutes and are comprised of three filter elements.

The first filter element blocks high-speed data on the incoming phone line to the alarm panel modem, but allows the alarm modem's voice-band data signals to pass uninhibited.

A second filter element minimizes line seizure impedance disruptions on the outgoing connection to the household wiring. This filter also minimizes the loading effect the alarm panel might have on the PC or home phone line network devices, allowing these devices to operate at peak data rates.

Finally, a high-pass filter element delivers the DSL signal to the household wiring without affecting the operation of the alarm panel. Thus, DSL communication can continue uninterrupted during line seizure and incident reporting.

Improved Satisfaction

The net result is the DSL signals never conflict with the alarm panel dial-out, the panel can take control of the line in an emergency while maintaining the DSL signal for video or health monitoring systems, and the customer enjoys the full benefits of both services.

Many security installers and alarm providers are using these relatively new alarm panel DSL filters to increase customer satisfaction of existing clientele and to secure new business. Some alarm providers are proactively installing the filter with every new alarm system, whether or not the homeowner currently subscribes to DSL. Other alarm providers send the filter to their customers and allow them to self-install the filter, following up with a system test to ensure proper functionality. A well-trained installer can even demonstrate how the alarm filter improves DSL data rates on the customer's PC.

Today's high-tech homeowners want service and support from providers they can trust. Simple solutions such as alarm panel filters give security installers the edge to ride the wave of Internet convergence.

Millard Schewe is marketing manager of Excelsus, a supplier of DSL filters (www.excelsus-tech.com). Schewe has more than 10 years of experience in the security and telecommunications industry.