
FAQs (Frequently
Asked Questions)
First
time buyers of security
systems often ask questions about what they should buy. They ask
friends who have systems and
salespeople who sell them.
The following questions and answers will help explain some of the many qualities you should look for in a security system… and separate them from the bias of sales people.
Should
every door and window be protected?
Every
accessible door and operable
window should be protected if practicable and also depending on cost to
the customer. All glass windows should be protected with some sort of
shock/audio
detector. Windows can also be protected using alarm screens instead of
contacts and shock/audio
detectors. Obviously in a three story residence, the windows on the
third floor cannot be opened by
normal means; screens, vibration sensors or audio detectors should be
sufficient if the windows are
kept locked. Rather than contacting these third floor windows, the
money could be spent on
additional interior protection or other security features like fire
detection. However, if you would
feel unsafe with these windows uncontacted, contact them. It's your
security and your peace of mind.
Garage
overhead doors are a special
case. A lot of people get these doors contacted and then pay extra to
have the door bypassed
automatically when the garage door opener is used. Since the only way
to open these doors is by
using the garage door opener, they are paying for the door to be
protected and then paying more for
it to be unprotected. Don't spend money to protect a door and then
spend more to bypass the
protection every time the door is used. Spend your money on additional
protection or added features.
Should
the contacts used on windows be visible or recessed in the frame?
This
depends on you and your installing company. Does the burglar seeing
the switch go elsewhere because he now knows you have more than just a
sign and some decals? Can the
burglar defeat the contact just because he can see it? Some people
cannot tolerate the sight of
normal surface mounted contacts or feel unsecure because "the burglar
knows what's there."
Other people feel secure seeing the
switches
because "the burglar knows I really do have a system installed by a
professional." Surface
mounted switches often are easier to install. Although the price for
installing recessed switches
may be higher with some companies, generally prices run the same for
either switch.
One
hype concerning recessed
switches is the size of the switch in a wooden door or wooden door
frame. If the switch is recessed
in the frame, you cannot see it when the door or window is closed. As
long as it fits the frame
properly without overlap, it does not matter what the diameter of the
switch is.
What
are EOL resistors and why should I have them?
An
End-Of-Line resistor supervises
the wiring between the alarm panel and the switch. Some panels have a
limited number of detection
zones and do not require EOL resistors. But if the panel can use EOL
resistors to supervise the
wiring, the resistors should be used. If more than one detection device
is on a single detection
circuit, the EOL should be at the last device. When feasible, every
alarm detection device should
have an EOL resistor at the device. If the EOL resistor is at the
burglary contact on a door, the
panel sees the wire open when the door is opened and sees the resistor
when the door is closed. The
thief who shorts wires together hides the EOL resistor from the panel,
letting the panel know that
something is going on. The thief who cuts the wire causes an open
circuit, the same as if he had
opened the door.
Hold-up
alarms and Fire alarms use
an "open circuit" detection scheme. The panel normally sees the EOL
resistor at the end of
the detection circuit. A short on the wire causes an alarm and a break
in the wire causes a trouble
report.
Where
should EOL resistors be installed?
What
makes EOL resistors so
important is that they can supervise the wires only when they are at
the end of the line. When
properly placed in the circuit, EOL resistors prevent wire tampering on
normal switches. EOL
resistors in the control panel are usually ineffective. The usual net
effect of putting the EOL
resistors in the panel is that the panel acts as if it has no EOL
resistors. Even open circuit
devices like smoke detectors and hold-up buttons are not properly
supervised when the EOL resistor
is attached in the panel before the end of the line.
Should
I get a wired system or a wireless system?
Many
factors affect this choice.
The major factor is the construction and decoration of the premises.
Can the location be wired and
how much labor will be involved in wiring for the alarm? Will wireless
devices be able to
communicate to the alarm panel? Plaster walls with metal lathe in them
can block the wireless
signals. Large mirrors, foil wallpaper, metal lockers and other radio
systems nearby might prevent a
wireless system from working properly.
QUESTIONS ABOUT WIRELESS SYSTEMS
How
often must the batteries be changed?
What
is the cost to replace the batteries
What
about fire safety?
This is a security issue
that is too often overlooked. Most homes have
smoke detectors installed, but what happens if no one is home when they
go off? More importantly,
what if you don't wake up because carbon monoxide puts you into a
deeper sleep?
A simple but priceless
solution is to have at least one monitored
smoke/heat detector to supplement the others in the house. This way,
the fire department will come
whether you are able to call them or not.
Sydney Division
Sydney office is the administration office for monitoring and development of new technical security products, as well as providing technical support to service personel, and qualified teaching staff for electrical theory and security electronics, both to our staff and to student installers.
Central Coast Division
Central Coast Division provides patrol and technical security services in the central coast area, and has access to all technical service information available from Sydney, a pool of nearly 60 years experience in security electronics. Patrol services provide efficient and well trained officers to oversee your security and assets.

