12 M VOLUMETRIC LENS - Standard lens used on PIRs. Gives full room coverage made up of 24 beams.

20-MINUTE CUT OFF TIMER - Standard timer built into all bell boxes. Used to ensure that bell box stops once it has sounded for 20 minutes. It is set at 20 minutes to comply with The Environmental Noise & Pollution Act 1987. 15 minutes is now the norm for bell on operation

3- WATT STROBE - This is a U-shaped strobe, used on some bell boxes. It is not only brighter, but will also last approximately 2½ times longer than the l-watt version.

30 M LENS - This is an optional lens available for some PIRs. The angle of coverage has been made narrower which in turn sends the PIR beams further (30 metres). Suitable usage would include corridors.

ABS - Stands for Acrylo-nitrile Butadiene Styrene. This is a soft plastic, which is generally used for PIR mouldings.

ACCESS - This zone type is also known as a walk through zone. It is particularly useful if, when entering the premises you have to pass a PIR to get to the control panel. It will only allow you to walk past if the entry/exit zone, i.e. the front door, has been opened first. If any other means of entry is used it will trigger an immediate alarm condition

ACPO - Association of Chief Police Officers

ADVANCED TEMPERATURE COMPENSATION - This is a feature found on some PIRs. It will adjust the threshold levels on the unit, as the background temperature of the room changes, i.e. through heating coming on. This helps to prevent false alarm activations that can be caused by temperature changes.

ALARM ABORT - This is an ACPO recommendation, to reduce false alarm calls to the monitoring station. This feature is built-in as standard to certain panels. If when coming into your premises you accidentally trigger a sensor, this will send a signal down to the monitoring station, which would automatically be treated as an alarm activation. The abort facility allows you to cancel this, by sending a second signal to the monitoring station. You do this by re-entering your user code, within a programmable time window.

ALARM B -This is an ACPO recommendation, to confirm those alarm signals sent to the monitoring station are the genuine article. This is also known as sequential verification. This feature is built-in as standard to some panels. It works by sending two signals instead of one, within a 30 minute time window. Two different zones must trigger this signal, to verify that it's not a faulty unit, but a genuine alarm condition.

ALERT - This zone type would be used for monitoring of a freezer in a supermarket for example. In the un-set condition, if the freezer failed it would activate the internal -sounders. In the full-set condition it would notify the monitoring station, via the communications equipment. One thing to note is this zone type would never activate the external sounders

ALERT KEYS - On some control panels and remote keypads, there are alert keys. Dependent on which panel you use, it is either fixed on keys 1 & 3, or programmable. If these keys are pressed simultaneously it will activate the external sounder. It also saves the engineer having to use a zone on the panel itself for a panic attack button

ANTI-MASK - Anti-mask is a feature built into a number of detectors that recognises if someone is try to mask the detector, effectively jamming the beam array to prevent the detector picking up motion. If an attempt to mask the detector is detected, the alarm will be activated

ARC - Alarm Receiving Centre. A secure location where signals are monitored 24hours a day.

AUDIO VERIFICATION - This is another means of confirming an alarm signal to the monitoring station, in line with the ACPO policy. It works by having microphones situated around the premises. When the monitoring station receives an alarm signal they can ring though to the premises, which in turn will switch the microphones on and allow them to listen quickly to any activity.

BACK TAMPER - Available as standard on the majority of bell boxes. The tamper generally comes in the form of a micro switch. If an intruder attempts to pull the unit away from the wall, the tamper will activate causing an alarm condition. All NACOSS customers use rear tampers in line with their procedures.

BELL DELAY TIME - This is only recommended for use on an alarm system with communication to a monitoring station. It is a programmable time that delays the bell box from activating in the event of an intruder activation. The signal to the monitoring station still goes out immediately, but any bell boxes or internal sounders will not go off until the delay time has elapsed. This means that there is more chance of the police actually catching the intruder, rather than just frightening them away.

BELL ON TIME - This feature is programmed into the panel by the engineer. It is the length of time he wants the bell box to ring for, in the event of an alarm condition. There will normally be a backup 20-minute timer built into the bell unit itself, but this will only be used if the power between the panel and bell is severed.

BLANK END STATION - This phrase applies to any control panel, which does not have a keypad on-board to operate engineer and user functions. It will come in the form of a polycarbonate or metal blank box. All programming functions will need to be done from a remote keypad

CALL PARKING - This is a means of preventing telephone calls on a shared line being blocked, done in conjunction with BT star services, which is similar to call waiting. It works by parking any incoming calls, while it sends the signal out. It is recommended that this be used with a Speech Dialler or digital communicator so, in the event of an alarm, the communications equipment has no problem dialling out.

CEILING MOUNT BRACKET - This is a standard bracket for use with most of our PIRs. It would be mainly used when it is difficult to mount the PIR in the corner, in particular when there is coving in-situ.

CHIME - This zone control is mainly used on shop doors. It is used to indicate when the door is opened. It does this by emitting a duo-tone, which can be done by either the panel or internal sounder. Chime can be used on any zone, with most control panels. Other uses may include the chime being used in conjunction with a PIR at the top of the stairs, to notify when small children are at risk from falling.

CLEANER CODE -This feature is available on some control panels. It allows one to allocate zones to a user code so that, when a code is entered, only the zones allocated will un-set. All remaining zones on the system will still be fully active. Useful applications would include a bank where it would be possible to alarm the safe room whilst leaving the office area un-set to allow the cleaners to do their job.

COVERED PCB -This is a lacquered PCB with a cover secured over the top of it. This will give some formal weather protection, but is by no means as effective as encapsulated modules

CREEP ZONE - Creep zones can be found on the majority of PIRs. PIRs send out a series of beams to give full room coverage. Creep beams are sent out just in front of the unit, to pick up on an intruder trying to tamper with the unit itself.

CURTAIN LENS - This is an interchangeable lens available for all of our PIR units. It changes the beam pattern to a straight vertical coverage, used across a doorway for example.

DB OUTPUT - The sound output from all sounders, internal or external are measured in decibels. By law this cannot exceed 125dB.

DIGI CHANNELS - The channels on the digi or digicom (digital communicator) are used to send information from the panel to the monitoring station. This information will notify them of the type of alarm condition, i.e. intruder, fire, etc. The panel/digicom used determines the number of channels available for this purpose.

DIGI PROGRAMMER -This tends to be a hand held unit in the style of an LCD keypad. It enables the engineer to programme the digi, prior to it being installed. The benefit of this approach is that the alternative is to purchase a chip from the monitoring station, with the programming on. This chip creates further additional costs for the installer.

DIGITAL COMMUNICATOR - Otherwise known as a digi or digicom. The communicator is there to transmit the alarm signals to the monitoring station; it does this using DTMF, (telephone talk). The only time the communicator will transmit to the monitoring station is in an alarm condition or on a test call. The most common communications protocol is BSIA Fast Format.

DUALTECH - A Dualtech is a dual technology detector which uses both PIR and microwave technologies to detect movement. For the detector to alarm, both the PIR and microwave technologies need to detect movement, thus reducing the risk of false alarms.

DURESS CODES - This feature is available on some control panels, and is used in conjunction with either a digital communicator or a STU. If you are under attack, and are being forced to open the premises, there are two ways of activating a duress signal; either through a dedicated code or by upping the first digit of your user code by one (for example, if your code is currently 2345, you would input 3345). This will still un-set the system but at the same time send a duress signal to the monitoring station, so that they can alert the police. The major benefit of this feature is that the signal is sent out but the bells are not activated.