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Car Security – A Classification Alphabet Soup

Car security acronyms and shortened termsIf you are confused about car security it’s not really surprising, with an alphabet soup of acronyms and shortened terms. Do you know your TRI from your TQA? Your CAT1 from your CAT2? Here we try to guide you through the classification minefield.

TRI – Thatcham Recognised Installer

This programme began in January 2010 and is a network of installers for the UK . Installers use a Thatcham database to enter individual car details, customer details, date, security device details, and their installer code.

MESF - Mobile Electronics and Security Federation

A well established network of installers and technicians for vehicle security, mobile media, tracking, communications, aftermarket equipment and auto electrical services. They also provide training and courses for installers.

VSIB – Vehicle Services Installation Board

Unfortunately this organisation went into receivership and disappeared in April 2009.


This is short for ‘Category 1’ and means the devices are car security alarms designed for cars, vans, leisure vehicles or HGV. Insurance companies will often ask car owners to have a ‘CAT 1 Car Alarm’ fitted as part of their policy agreement.


Short for ‘Category 2’ and means a car immobiliser. This is the most basic form of vehicle security and stops cars from being easy to steal. Insurance companies will sometimes ask for a ‘CAT 2 Immobiliser’ to be fitted, and this is most common when insuring imported cars.

CAT 2:1 Upgrade

Sometimes cars are manufactured with a CAT 2 immobiliser. This device will upgrade a CAT2 to become a full alarm system and a CAT1. Often less expensive than starting again, and sometimes the only option for newer cars with CANbus wiring systems.


After theft systems for vehicle recovery capable of engine crank inhibition and a police level 1 response.

TQA – Thatcham Quality Accreditation

Often awarded to vehicle tracking systems, by Thatcham, to show each system has been vigorously tested against benchmark standards. The TQA is followed by a unique number for example all ToadTrak devices have a TQA-105 number.


Many TQA vehicle tracking devices are being also assigned as ‘Category 6’ systems. These include devices from Smartrack, Trafficmaster and ScorpionTrack. This change also meant that as of January 2011 all Smartrack devices can only be commissioned if fitted by a TRI installer.

Thatcham Approved - Alarms, Immobilisers, Trackers

This is a process where vehicle security manufacturers submit their products to Thatcham for vigorous testing. Once they have proved to be of the standard required they are given the term ‘Thatcham Approved’. Please note Thatcham approved alarms and immobilisers must be fitted by a qualified and affiliated installer to ensure installation standards are also met.

Last updated September 2011
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Website promotes the current recognised UK installer network. Car alarms should be fitted by either a Thatcham Recognised Installer or an MESF Approved Installer. © 2011