Home Location Register (HLR)
The HLR is the central database in a 2G or 3G mobile network that holds each subscriber's details and current location.
What is Home Location Register (HLR)?
It stores IMSIs, phone numbers, service permissions and the area the subscriber was last registered in, so that calls and texts can be routed. In 4G and 5G it is replaced or extended by the HSS and UDM.