Predictable Response

There's a real need for authorities to receive timely, accurate information when an alarm occurs. Police officers respond more effectively when they’re armed with the exact sensor location that causes an alarm. Knowing the location of the alarm based on information provided by the central station enables responding authorities to go directly to the correct section of the building.

In the past, first responders had no idea where they where headed in a large building before they arrived. Not even the central station’s operators could determine which sensor was tripped, because all the building’s alarm devices were tied to a single initiating device circuit (IDC).

In the 1970s and ’80s, security system technology advanced to the point where alarm panels were equipped with two or three IDCs. For example, the first models to be released had an exit/entry, a perimeter and an interior zone.

Although this may appear restrictive by today’s standards, at the time, it allowed security dealers to minimally, logically zone their burglar alarm systems. A good example is the placement of an exit/delay door on a zone; one or more interior motions on a zone; and all the perimeter, instant doors and windows on a third. At least responding police officers had a general idea where to go.

The next logical move was for manufacturers to expand the capacity of their panels. The result was alarm panels to which many banks of IDCs could be added. The information gives first responders, end-users and alarm technicians a decisive advantage from the standpoint of response, convenience, ease of service and a general cost savings.

Make the addressable connection

The introduction of conventional, multiple--IDC alarm panels has proven to be a tremendous advantage for all concerned. But there still are times when a slew of IDCs is not enough. This is especially true when working in larger facilities, such as high-rise and multiple-floor tenant buildings.

One alternative to IDCs and zoning is addressable technology. This means an alarm panel can quickly determine the exact location of the burglar’s whereabouts. The same technology will offer up additional information about each sensor through a process called polling.

“There are several reasons why addressable is better than conventional. For one thing, you get more information. … [A]n addressable point, such as a motion detector, can tell you not only if it’s in alarm, but whether the cover has been removed or if there is some other kind of trouble within the device,” said Tom Mechler, product marketing manager, Bosch Security Systems of Fairport, N.Y.

“You can address hundreds of sensors, so addressable systems can drastically reduce installation costs,” Mechler said.

By contrast, when it is necessary to identify the exact sensor that has gone into alarm, conventional panels require that the installer homerun a pair of wires to each sensor. With addressable technology, the installer merely daisy-chains them together.

Addressable burglar alarm systems typically can be installed using less metallic wire than their conventional cousins.

Addressable installation is straight-forward, entailing the use of a two- or four-conductor cable. This cable typically is installed device-to-device in a serial manner. Where four conductors are involved, two are used to carry operating power, while the other two carry sensor data.

In the case of the MaxSys alarm panel (Digital Security Controls, Concord, Ontario), only two conductors are required to power and monitor an addressable device. In this case, the same pair of wires that provides operating power also provides data communication. Installers can connect up to 128 devices on a single SLC with the MaxSys alarm panel, or a number of devices can be placed over the span of two SLCs.

Often, the same panel that offers addressable capability also will provide conventional IDCs. This is done by placing eight or 16 IDCs on the motherboard along with one or two SLCs. IDC capacity also can be enhanced by using IDC expander boards.

Most addressable alarm panels on the market today also support fire detection. The code requires that a separate SLC be used for life safety when the same panel serves burglar and fire alarm functions.

Usually, an add-on digital alarm communicator transmitter (DACT) module is required with two telephone lines for central station monitoring. This module supervises both phone lines to ensure the panel communicates with the remotely located digital alarm communicator receiver. The dual-phone line portion of the DACT is designed to switch from primary to secondary phone line when one or the other becomes inoperative. Some of this may become moot with the inclusion of Internet protocol, such as in the case of Fire Lite Alarms’ IPDACT.

As a general rule, addressable alarms cost more than conventional systems, but there are definite advantages. One is the additional information, and another is a general cost savings in service charges after the warranty period expires.

COLOMBO is a 32-year veteran in the security and life safety markets. He currently is director with and a nationally recognized trade journalist located in East Canton, Ohio.

About the Author

Allan B. Colombo

Freelance Writer
Allan Colombo is a 35-year veteran in the security and life safety markets. He is director with and a nationally recognized trade journalist in East Canton, Ohio. Reach him at

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