Abstract: A method is provided for a telephone subscriber to distinguish between callers. The method is accomplished by storing a pass code for a subscriber's telephone within a memory of the telephone system. Callers who have been informed of the pass code and who call the subscriber's telephone and enter the pass code receive special treatment. For example, upon the caller calling the subscriber's telephone, a normal ringing pattern is applied to the subscriber's telephone while a ring back signal is returned to the caller. Upon the caller entering the pass code, a special ringing pattern is applied to the subscriber's telephone. The special ringing pattern is different than the normal ringing pattern and thus indicates to a subscriber of the subscriber's telephone, even before the telephone is answered, that the caller is one of a select group of callers to whom the subscriber has shared the pass code.

Abstract: A method of Distributed Call Control is provided in a Distributed Transit Private Branch Exchange (PBX) comprising a plurality of Nodes forming a wide area network, and a plurality of D-channel Server Modules (DSMs). The DSMs are located in predetermined ones of the Nodes with each DSM coupled to at least one associated PBX via at least one D channel. The method includes the following steps. First, a listing of all Exchange Codes (ECs) handled by a DSM and each associated PBX coupled thereto is stored in a local routing table of a memory in the DSM. Second, a listing of all ECs handled by all of the other DSMs of the Distributed Transit PBX and their associated PBXs is stored in a remote routing table of the memory in each of the DSMs.