Abstract: A PBX call discrimination system which provides voice, FAX, and data services utilizing one telephone number (DID) for each local line being serviced. The PBX connects incoming lines to local lines serviced by it. Each local line is identified by a DID received in a call setup message on the incoming line. The PBX stores information associating a voice call extension, a FAX line, and a modem line with each DID. The PBX identifies an incoming call as being a voice call, a FAX transmission, or a data transmission. The incoming call is connected to the FAX line associated with that DID if the incoming call is identified as a FAX transmission, and to the modem line associated with that DID if the incoming call is identified as a data transmission. FAX and modem servers can be connected to the PBX for directing FAX and data transmissions, respectively, to the intended called party. The routing information utilized by such servers is provided by the PBX.