There are two categories of Thatcham alarm, category 2 to 1 alarm upgrade and category 1 alarm and immobiliser. If you have a newer UK specification car it will have a factory fitted Thatcham category 2 immobiliser so you will only need a 2 to1 upgrade. For older cars or ones that have been imported privately you will need a full Thatcham category 1 alarm and immobiliser.
Thatcham do not manufacture car alarms, they set design standards for car alarm manufacturers to meet and each alarm is given an evaluation code if it passes and makes it onto the Thatcham list of car alarms. Some of the well know Thatcham car alarms are; Clifford Avital, Clifford Concept, Cobra, Gemini, Meta, Toad and Viper.
A Thatcham cat1 alarm will have an ultrasonic sensor to protect the interior of hard top cars but open top cars must be fitted with a microwave sensor in place of the ultrasonic sensor. The immobiliser part has at least two circuit protection; this can be the fuel pump, ignition circuit or starter motor. Other features of a Thatcham alarm are a high security remote control that cannot be copied and self power siren which stays on after the wires are cut.
The remote control that comes with a Thatcham alarm operates both the alarm and central locking system, so if you previously had key operated central locking you can now lock and unlock the doors by remote control. Some of the more expensive Thatcham alarms have extra buttons to open the luggage area independently.
Extra security modules can be added to a Thatcham alarm such as; automatic electric window closure, tilt sensor, radio pager, SMS text message pager, dual zone pre warning bleep or glass break sensor.
For more information please visit http://www.electrifyingtouch.co.uk