Time division digital communication system
First Claim
1. A time division switching system for providing two-way communication between a plurality of circuits arranged in a plurality of groups, said system comprisinga time slot interchange having a plurality of groups of memory sections each corresponding to at least one of said circuit groups, said memory sections each having a plurality of memory locations each corresponding to a different one of the sequential time slots of the plurality of circuits in its corresponding circuit group,a plurality of send highways between said corresponding circuit group and memory section group,a plurality of receive highways each for a separate one of said circuit groups,means for connecting each of said receive highways selectively to any of said memory sections,timing and control means for transmitting data signals simultaneously in each of said time slots along said send highways from all of said circuit groups to said memory sections for storage in different ones of said plurality of locations and for transferring data signals stored in said locations selectively to different ones of said receive highways to the circuit group therefor through said connecting means in different ones of said time slots to provide bidirectional communications among any of said circuits in the same circuit group and in different ones of said circuit groups.
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Abstract
A time division digital communication system which does not require a common control unit for accomplishing interconnections, having a plurality of modular switching units. The switching units are identical and each unit has its own port circuits to which subscriber lines and/or trunks may be connected, service circuits, a time slot interchange and a microprocessor control and timing unit. The switching units are in direct communication via separate send highways, one for the port circuits and the other for the service circuits of each switching unit. The microprocessors of each switching unit are also in direct communication by way of control lines. The inter-switching unit send highways are connected to separate channels or groups of memory locations in the time slot interchanges of each of the switching units. By selective listening to receive highways connected to the output of the time slot interchanges, any port or service circuit, whether in its own switching unit or any of the other switching units, can be interconnected. These interconnections are made under microprocessor control on the basis of events such as off-hook conditions and dialed digits from the ports, rather than by central or call processing. The switching of calls is non-blocking, as any port can be connected to any one or more of the other ports or service circuits at all times.
52 Citations
20 Claims
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1. A time division switching system for providing two-way communication between a plurality of circuits arranged in a plurality of groups, said system comprising
a time slot interchange having a plurality of groups of memory sections each corresponding to at least one of said circuit groups, said memory sections each having a plurality of memory locations each corresponding to a different one of the sequential time slots of the plurality of circuits in its corresponding circuit group, a plurality of send highways between said corresponding circuit group and memory section group, a plurality of receive highways each for a separate one of said circuit groups, means for connecting each of said receive highways selectively to any of said memory sections, timing and control means for transmitting data signals simultaneously in each of said time slots along said send highways from all of said circuit groups to said memory sections for storage in different ones of said plurality of locations and for transferring data signals stored in said locations selectively to different ones of said receive highways to the circuit group therefor through said connecting means in different ones of said time slots to provide bidirectional communications among any of said circuits in the same circuit group and in different ones of said circuit groups.
- 11. A TDM telecommunications system for providing two-way communications between a plurality of lines, said system comprising a plurality of switching units each serving a separate group of said lines, each of said units having port means interfacing with said lines for receiving and transmitting digital signals, time slot interchange means, and processor means, a send highway and a receive highway, said time slot interchange means, processor means and port means interfacing with each other to provide time division multiplexed receiving connections for digital signals through said time slot interchange means and receive highway, and time division multiplexed transmitting connections along said send highways to said time slot interchange means, and said switching units being in direct communication with each other via control lines interconnecting the processors thereof and said send highways interconnecting the time slot interchanges thereof.
Specification