A system for providing a personal location, access control and asset tracking service using an in-building telephone network is disclosed. In a first embodiment, users of ID badges containing an RF transmitter can be located across the telephone network for receiving incoming calls. Receiver units in or near telephone sets instruct the system of the identity of the user located near the telephone set. In another embodiment, access to a building or rooms therein is controlled according to the identity of the ID badge wearer. Similar receiver units located at building and room entrances receive the RF transmission from the ID badge to allow or deny access to the rooms or building. In a third embodiment, ID tags placed on material assets permit the system user to monitor the movement and location of specific material assets associated with that ID tag. The ID tag also contains an RF transmitter which is used to transmit an RF burst to receiver units located across the telephone network.