Signaling protocol channel unit
January 13, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInterface for in band SCPC supervisory and signalling system Multifrequency sender/receiver in a multi-time slot digital data stream Call state processor for a time division switching system Digital trunk supervisory decoder multiplexor for ground start or E&M signalling on a common T1 span Radiotelephone communications system Impulse metering of local telephone switching offices via a DAMA DOMSAT communication system Patent #: 4273962 InventorsAssigneeApplicationNo. 06/563193 filed on 12/19/1983US Classes:379/240, Interexchange trunk circuit370/522Signaling (ancillary to main information)ExaminersPrimary: Brown, Thomas W.Attorney, Agent or FirmInternational ClassH04Q 11/04 (20060101)AbstractDisclosed is a channel unit for directly interconnecting a toll office multiplex carrier channel line and a terminal unit line such as that of a private branch exchange (PBX) or a telephone station set, thereby eliminating the normal local end office interconnection. In particular, the channel unit interfaces the different signaling protocols of the two lines and generates call progress controls signals such as dial tone and audible ringing which are normally generated by the local end office. The channel unit comprises a converter for each line for converting the electrical interface signals representative of the busy and idle conditions of the line to logic level signals also representative of the busy and idle conditions of the line. A predetermined series of these logic level signals form a control signal that indicates the state in one signaling protocol of a call on the line. Since the control signal indicative of the state in one signaling protocol of the call on one line is typically not useable by the other line, a microprocessor included in the unit generates a second control signal to advance the state in another signaling protocol of the call on the other line to an equivalent call state. An additional converter then converts the logic level signals of this second control signal to the electrical interface signals of the other line to advance the state in the other signaling protocol of the call to the equivalent call state. The unit further comprises a receiver and transmitter for exchanging dial pulse and dual tone multifrequency address signals between the lines. Also, included are circuits for applying call progress control signals such as dial-tone, audible ringing, and power ringing to the lines.Other References
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