Abstract: A cellular telephone or other wireless mobile user equipment (UE) can be located with greater than cell precision by monitoring for transmitted radio signals at landline telephone sites, such as offices in a building. At each site, a telephone instrument device not only performs functions characteristic of a conventional desktop or landline telephone instrument, but also detects radio signals emitted by any nearby UE. Any detected signals are transmitted from the landline telephone site to a central monitoring location. The central monitoring location receives some or all of the transmitted signal information as well as information identifying the landline telephone site at which radio signals emitted by a UE have been detected, such as a landline telephone number. The telephone number is then used to determine the location of the landline telephone site.