A private branch exchange (PBX) (118) system that routes calls within a packet-switching network (106). Login information is received from a data device (102). The login information includes an alias identifying a user at the data device (102) and a network address identifying the location of the data device (102) on the packet-switching network (106). The virtual private branch exchange system associates the user's PBX (118) extension with the network address and routes calls to the user's PBX (118) extension to the data device (102) on the basis of the network address of the data device (102).