Shared mapping of a station extension within a distributed, enterprise telecommunications system, to an associated telephone number

A method is disclosed that provides the sharing of a station-mapping description with a first private-branch exchange, where the description has been initialized and maintained at a second private-branch exchange. Such a description describes a logical association between a station extension of an enterprise deskset and a telephone number of an off-premises terminal, such as a cell phone. As a result of the sharing across private-branch exchanges, an incoming call from a second employee's cell phone can be recognized, by a first employee being called, as coming from the calling second employee. This is because the incoming call is identified with the telephone extension of the calling employee's deskset terminal in spite of the call being placed from the cell phone, or other telephone number at large. This is particularly important where a large company engineers its enterprise's telecommunications system across multiple private-branch exchanges.