Necessary and Secure Wireless

According to the federal bureau of investigation, reported burglaries increased by 3.5 percent in municipalities with a population of 1 million or more during the first six months of 2007. Violent crime increased by 1.1 percent in nonmetropolitan counties and in cities with a population of 10,000 to 24,999.

Such data has caused the public to be more security conscious. News about terrorism has convinced home and business owners that electronic security is more than a luxury. No one wants to become an FBI statistic.

According to a report titled “U.S. Physical Security Equipment Markets,” published by Frost & Sullivan of Rockville, Md., “Americans now view security systems as a necessity rather than a precautionary measure for the home and workplace. Due to highly publicized incidents, the fear of crime and terrorism is driving demand for security equipment. Technological advancements and fierce competition in certain market sectors have made physical security equipment more affordable and reliable.”

Of special interest in the area of alarm systems is the widespread adoption of wireless technology. Although wireless has been available in the security sector for decades, market forces have driven the general public to accept and trust a wireless solution. The popularity of the cell phone and all its variations is probably one of the most prominent.

More installing companies are turning to wireless for a variety of reasons.

1. Ease and simplicity of installation

2. Less dependence on unstable metallic wire prices

3. Lower labor costs

Why radio instead of cables

In some applications, it is extremely difficult or impossible to run or hide a wire. For example, there is no easy way to hide wires in the common A-frame retrofit application. Other examples include slab construction where there is no basement, cases where there is a second story on slab construction, and where there is no attic available to run wires.

The first wireless systems used add-on receivers that connected to a single initiating device circuit (IDC) or zone input. This approach, rarely used today, had its disadvantages.

These early wireless systems, made in the 1970s, were somewhat effective, but they lacked individuality. They were not able to discern one transmitter from another, which made it impossible for technicians to quickly determine the cause of false alarms, worn-out batteries or trouble indications.

Wireless reliability and costs

A growing number of equipment manufacturers now make wireless transmitters to which motion detectors, temperature sensors, door sensors and other devices connect. These multiple--identity receivers are capable of conveying individual transmitter identifiers to the main alarm control processor for analysis and action. Because of this, today’s wireless security alarms are reliable, predictable and convenient.

Troubleshooting consists of reading the name or location of an offending sensor from an English-language readout keypad. The same information is sent to the central monitoring station, where operators analyze and act on it, notifying the authorities, the installation company and end-user when necessary.

The use of a unique identifier, as well as a general reduction in the amount of wire used, have led to widespread acceptance of wireless security systems among installation companies and consumers. This promises to reduce the amount of metallic wire used in a typical alarm system, which also will reduce the overall cost to the client.

Less metallic wire also means less labor. Labor often runs neck-and-neck with the cost of the material on an alarm installation job. When you factor in all the unknowns, labor can even outstrip equipment costs.

For this reason, many experts in the security field believe that wireless removes all the guesswork from the bidding process. It changes labor from an unpredictable element into a known quantity.

The mechanics of wireless

There are three basic types of security systems in use today: hardwire, wireless and hybrid. No matter which one you use, a typical security system consists of four elements:

1. Control system

2. User interface

3. One or more people sensors

4. A means of notification

In hardwired systems, metallic wires are used to electrically connect door switches, passive infrared (PIR) motion detectors, smoke and fire detectors, and other devices to the main alarm control panel. Two conductors typically are used for detection and two for power.

By contrast, in a typical wireless system, sensors and detectors contain small transmitters that are self-powered. Door/window and small pendant transmitters commonly use a lithium battery, which can last for five to eight years. Smoke detectors and motion sensors generally contain a 9-volt battery. Some of the alkaline models now on the market are designed to last two years or more.

The hybrid system is a combination of hardwire and wireless, having provisions for metallic wire with the convenience of wireless technology. This type of system offers hardwire inputs just like any strict hardwire system. In some cases, wireless is optional, while in others, it’s integral to the alarm panel.

In a component style system, wireless capability is added by installing a separate receiver. Often, this is accomplished by connecting the receiver module to either the keypad circuit or a special data bus. In some cases, more than one receiver can be added to a single alarm control panel.

One benefit of the component method is the ability to place a -receiver in a different location than the alarm panel. This is helpful where the alarm panel is installed in a basement or an area that may not be conducive to the reception of radio signals. The receiver can be placed on the first floor where it can readily “hear” sensor transmitters.

The importance of using the first floor as a receiving point for wireless transmitters cannot be stressed enough. Receivers mounted above earth ground have a much better chance of “hearing” sensor transmitters located throughout the home or small business than those mounted below ground level.

Supervision and redundancy

Today’s wireless technology allows the low-voltage contractor to supervise each device so that the exact transmitter causing an alarm is readily known. This is accomplished using both passive and active supervision.

In a passively supervised system, wireless sensors will report a problem when it occurs. Supervisory reports are subsequently tailgated with other signals, as with “door open” or “door closed” status signals. Along with the open or closed condition of the door, sensor transmitters also may include low-battery signals, thus alerting the main alarm panel when a transmitter needs attention.

Active supervision takes a more aggressive approach. Low battery and other status information is transmitted as soon as a symptom occurs in addition to supervisory signals sent to the receiver on a regular basis at a predefined frequency.

If the alarm panel fails to see this special supervisory signal within a given time period, such as eight or 24 hours, the alarm panel will assume something has happened, and the central monitoring station will be contacted with the appropriate information. This gives the operators on duty the heads-up, so they can call the installing company, end-users and anyone else who should be informed.

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

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.