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Personal Security Systems
T E Electronics PERSONAL SECURITY SYSTEMS make use of an Infra Red "Keyfob" transmitter to alert a control centre that there is an alarm and the location of that alarm.

Application areas include new systems or upgrades of existing push button systems in

  • Schools
  • Social Security Offices
  • Prisons
  • Hazardous environments Personnel Monitoring


The signal from the KEYFOB TRANSMITTER is picked up by local wall or ceiling mounted receivers which can be internal or external. Each receiver can be directly wired to the control centre or can communicate via a coded radio signal sent from an inbuilt transmitter. In both cases the control centre indicates the alarm and its location and the appropriate response can be initiated.


The keyfob is fitted with a keyring which is arranged as a "snatch trigger", ie if the keyring retaining tab is broken, the transmitter goes into permanent alarm transmission mode.

For systems requiring TWO LEVELS OF ALARM, keyfobs are produced with two buttons, one red and one blue. Pressing the red button, or both buttons, signifes a top level alarm.



Each wired receiver has two sets of volt-free relay contacts, corresponding to each of the two possible keyfob buttons. Receipt of a valid signal causes a relay to changeover and the red indicator LED to show. This state persists for the duration of the received signal plus about 10s.

Internal jumpers determine whether the relays are normally energised or normally de-energised and can select both relays to operate for single button systems.

Receivers are fitted with tamper switches which cause an alarm state if the unit is detached from its mounting. The cover fixing screws can be tamperproof types if required.

The supply voltage for the wired receivers is 12V dc or 24V dc. Quiescent current consumption is only 2mA per receiver for units operating with normally de-energised relays


are typically mounted on standard BS double plates and are compatible with 25mm deep standard electrical back boxes and fittings.

They can be surface mounted or can be flush mounted in suspended ceilings or dry-lined walls.

The standard plate type is white Urea Formaldehyde, but alternative plate types can be supplied on request.


are designed for situations exposed to the elements.

The external receivers are housed in IP66 Polycarbonate enclosures and are mounted on an assembly which has an adjustable hood and tilts the receiver slightly downwards.

The downward tilt is optimised for mounting heights of around 3m.

The hood shields the Infra Red sensor from direct sunlight (the sun is a powerful Infra red transmitter and can swamp the receiver with "signals").

The mounting plate is compatible with standard conduit outlet boxes or can be fixed directly to any surface.

Infra-Red Receivers with integral Radio Transmitters are known as "TRANSPONDERS".

The Transponder shown facing is part of the "ALARMLINK" Personal Security System which uses TE Electronics Infra Red technology to augment their radio technology. Direct Radio transmitters and IR activated transponders can be mixed in the same installation.

Each transponder and direct radio transmitter on a site is set to one of up to 255 unique codes to define the location. The Control Centre can be up to 100m or more away from a transponder.

Transponders are designed for internal use, surface mounted on a wall or ceiling. They are usually battery powered and installation requires NO WIRING.

The low current consumption of 0.5mA gives a battery life in excess of 12 months. However, in locations where mains powering is convenient the Transponder can be directly connected to the 230V ac mains. The system is proof against mains failure since it has an internal battery which is normally being trickle charged but can provide power to the transponder for 24 hrs.

The Transponder fixings are only accessible with the correct tamperproof tools. Attempts to remove the Transponder will automatically activate an alarm transmission.

Alarmlink_Txponder2_01.JPG (14870 bytes)

For further information on Alarmlink, visit