Alarm System Glass-break detectors- Glass-break detectors are also known as "Audio Discriminators". They are a perimeter device because they catch a burglar attempting to make entry into your home or business as opposed to walking around the interior and being picked up by a motion detector. They are available in both hardwired and wireless versions. The detector mounts in a wall or ceiling and listens to an area approximately 35 feet in all directions. They do not hear through walls or around corners or into a room because the door is open. The more windows you have in a device's area of protection, the better the value. Some examples of good coverage are as follows.

* If you have an open concept kitchen, breakfast nook and family room you can cover all the windows with one device because they are within the 35- foot area.

* If you have a living room with many windows you can cover them all because they are in the same area. Often the dining room is within the coverage area and can be protected with the same device.

* If you have an unfinished basement with windows, this is a very vulnerable area. You can cover all the windows with a single device in most cases.

The glass break detector listens for the frequency of breaking glass and splintering wood. In the not so distant past the only glass breaks available were "Single Technology" devices. These listened for the frequency of breaking glass and splintering wood only. The problem was that sounds such as lightning cracking, some peoples sneezes, clanking two glasses together in the sink or a pet bird squawking would replicate this frequency and cause false alarms that only the most cunning detectives would figure out.

Although the single technology devices are still being used today because they cost alarm companies less to purchase, a well-informed consumer would insist on the newer "Duel Technology" device. The new devices must hear a "Thump" and than a frequency hit, in that precise order in order to go into an alarm condition. Lets see if you understand what I'm telling you about the new technology.

Q: If you sneeze at the same time your bird lets out a squawk and this causes you bang your head on the wall, will this make your alarm go off if it is armed?

A: (NO) because it did not happen in the correct order. You would have to bang your head on the wall first.

This small advancement in the use of artificial intelligence has created a very dependable device that you can count on to defend your perimeter.

One of the downfalls of the sound discriminator is that they are costly and you need one in each room that is vulnerable. These would be accessible windows on the main or lower level or upstairs windows with roof or deck access. I recommend placing these devices in the areas of most concern and backing them up with a main floor motion detector. This way you don't spend your children's inheritance turning your home into Fort Knox.

(WISE WORDS!) The best security systems are the ones where you don't put all your eggs in one basket!

Matthew Francis Alarms@expertsknow.com

22 year veteran of the alarm industry Installer, salesman, licensed alarm company owner, monitoring station designer, promotions and marketing director with one of the worlds largest security dealers. He now works as a consumer advocate, teaching consumers how to buy or get systems for free (without being taken). He is committed to being unbiased. His web site is http://www.expertsknow.com