Equipment Identity Register or EIR in short is a database which contains the IMEIs of GSM Handsets which are being used to access a cellular network, IMEI is a code which is unique to every available GSM handset so with the help of Equipment Identity Register EIR the Mobile Operator can keep a track of all the handsets which are being used by its subscribers and in a case of any theft the particular handset can be barred from accessing the network and can be tracked further. EIR is an optional component in a GSM core-network and operators deploy it only if it is made mandatory by governing Telecom Regularity polices.

The EIR contains three lists of IMEIs in its database

– white list (handsets allowed to access the network)

– grey list (handsets to be observed)

– black list (handsets to be barred from network).