US3843849A — Multiple stage telecommunications switching netwo…

Claim 1

Independent Claim 302 words

A switching network including a plurality of cascaded stages, means for automatically completing a path through said stages from an input circuit requesting service to a network output circuit, each of said stages comprising at least one matrix, each of said matrices comprising a plurality of intersecting input and output multiples, means for coupling output multiples of preceding stages to the input multiples of succeeding stages to cascade said network, crosspoint elements positioned at the intersections of each input and output multiples to comprise said matrices, said crosspoint elements capable of being switched from a non-conducting state to a conducting state to interconnect said intersecting multiples in the conducting state, the invention comprising a control circuit connected to the output multiple conductors of said plurality of stages, said control circuit comprising means normally inhibiting the crosspoinT elements of a plurality of said stages to prevent said inhibited crosspoint elements from switching to the conducting state, said control circuit further comprising enabling means for successively enabling crosspoint elements of the output multiple conductors in the stage to which said control circuit is connected to enable successive crosspoint elements coupled between said input circuit requesting service and said enabled output multiple, and means for applying second signals to the output multiples of switched crosspoint elements for holding an operated crosspoint element in the conducting condition wherein said enabling means are operative during successive time intervals to switch a different crosspoint element during each of said intervals and wherein there are second enabling means operative during each interval to successively enable output multiple conductors of said second stage to switch crosspoint elements in a second stage of said network which are connected to the output conductor of a switched crosspoint element of said one stage and the enabled output multiple conductor of said second stage.

Claim 2

Dependent Claim 302 words

A switching network including a plurality of cascaded stages, means for automatically completing a path through said stages from an input circuit requesting service to a network output circuit, each of said stages comprising at least one matrix, each of said matrices comprising a plurality of intersecting input and output multiples, means for coupling output multiples of preceding stages to the input multiples of succeeding stages to cascade said network, crosspoint elements positioned at the intersections of each input and output multiples to comprise said matrices, said crosspoint elements capable of being switched from a non-conducting state to a conducting state to interconnect said intersecting multiples in the conducting state, the invention comprising a control circuit connected to the output multiple conductors of said plurality of stages, said control circuit comprising means normally inhibiting the crosspoinT elements of a plurality of said stages to prevent said inhibited crosspoint elements from switching to the conducting state, said control circuit further comprising enabling means for successively enabling crosspoint elements of the output multiple conductors in the stage to which said control circuit is connected to enable successive crosspoint elements coupled between said input circuit requesting service and said enabled output multiple, and means for applying second signals to the output multiples of switched crosspoint elements for holding an operated crosspoint element in the conducting condition wherein said enabling means are operative during successive time intervals to switch a different crosspoint element during each of said intervals and wherein there are second enabling means operative during each interval to successively enable output multiple conductors of said second stage to switch crosspoint elements in a second stage of said network which are connected to the output conductor of a switched crosspoint element of said one stage and the enabled output multiple conductor of said second stage.

Claim 3

Dependent Claim 54 words

A network as claimed in claim 1 wherein there is further control circuit means for enabling crosspoint elements in other stages, and for switching a crosspoint element in said other stages to complete a path from the output multiple conductor of a switched crosspoint element of said second stage to said network output circuit.

Claim 4

Dependent Claim 144 words

A telephone system comprising a plurality of cascaded matrices, each of said matrices including first and second multiples arranged to provide intersecting crosspoints, means for identifying one multiple in a first matrix of said cascaded matrices by an individually associated time frame, means responsive to simultaneous marking of multiples in first and last of said cascaded matrices for initiating a time frame scan during the time frame which identifies said marked multiple in said first matrix for operating an idle crosspoint in said first stage for the purpose of establishing a connection between said marked multiples, and means responsive to the initiation of said time frame scan for initiating a succession of time sub-frame scans in another matrix to find an idle crosspoint in said other matrix for connecting the marked multiple of the first matrix to the output multiple of said second stage.

Claim 5

Dependent Claim 144 words

A telephone system comprising a plurality of cascaded matrices, each of said matrices including first and second multiples arranged to provide intersecting crosspoints, means for identifying one multiple in a first matrix of said cascaded matrices by an individually associated time frame, means responsive to simultaneous marking of multiples in first and last of said cascaded matrices for initiating a time frame scan during the time frame which identifies said marked multiple in said first matrix for operating an idle crosspoint in said first stage for the purpose of establishing a connection between said marked multiples, and means responsive to the initiation of said time frame scan for initiating a succession of time sub-frame scans in another matrix to find an idle crosspoint in said other matrix for connecting the marked multiple of the first matrix to the output multiple of said second stage.

Claim 6

Dependent Claim 51 words

A system as claimed in claim 3, wherein there is a control circuit, and means for initiating the operation of said control circuit responsive to said simultaneous marking, said initiating means being redundant to provide a trouble signal in the absence of marking signals from one of said redundant initiating means.

Claim 7

Dependent Claim 274 words

A multiple stage switching network, in which each stage is comprised of identical matrix units, and in which each of said matrix units has input conductors and output conductors intersecting at crosspoints with outputs of one stage coupled to respective inputs of an adjacent stage, the invention comprising switching means at each crosspoint including at least three terminals, said switching means each having an enabling input terminal and first and second bias terminals responsive to signals applied to said terminals, each said crosspoint requiring two bias conditions and an enabling condition for operating the switching means at a crosspoint, said network operative in response to a signal at each end of said network in the form of a signal mark on one input conductor of a first stage and a signal mark on one output conductor of a final stage for initiating a path search through said network, between the marked input conductor of the first stage and the marked output conductor of said final stage, means in one stage for normally providing a first bias condition to one input of all idle crosspoints of said one stage, means for providing a second bias condition to one input conductor in said one stage responsive to a signal mark on said input conductor, and means for sequentially enabling one output conductor of said onE stage during each of a plurality of scan intervals to operate a switching means at the crosspoint between the one input conductor and the one output conductor of said one stage on the concurrence of first and second bias conditions and the enabling of the output conductor of said one stage.

Claim 8

Dependent Claim 274 words

A multiple stage switching network, in which each stage is comprised of identical matrix units, and in which each of said matrix units has input conductors and output conductors intersecting at crosspoints with outputs of one stage coupled to respective inputs of an adjacent stage, the invention comprising switching means at each crosspoint including at least three terminals, said switching means each having an enabling input terminal and first and second bias terminals responsive to signals applied to said terminals, each said crosspoint requiring two bias conditions and an enabling condition for operating the switching means at a crosspoint, said network operative in response to a signal at each end of said network in the form of a signal mark on one input conductor of a first stage and a signal mark on one output conductor of a final stage for initiating a path search through said network, between the marked input conductor of the first stage and the marked output conductor of said final stage, means in one stage for normally providing a first bias condition to one input of all idle crosspoints of said one stage, means for providing a second bias condition to one input conductor in said one stage responsive to a signal mark on said input conductor, and means for sequentially enabling one output conductor of said onE stage during each of a plurality of scan intervals to operate a switching means at the crosspoint between the one input conductor and the one output conductor of said one stage on the concurrence of first and second bias conditions and the enabling of the output conductor of said one stage.

Claim 9

Dependent Claim 74 words

A network as claimed in claim 5, wherein there is means for providing a first bias to crosspoints of a second stage, means for transmitting a signal from the conductor of an operated switching means of the one stage to an input conductor of said second stage, and means for successively enabling output conductors of said second stage during each scan interval to complete a serial path through said one and said second stages.

Claim 10

Dependent Claim 69 words

A network as claimed in claim 5, wherein the crosspoints of another stage are permanently enabled during a path search through the network and means for operating one switching means in said other stage on a marked output conductor are responsive to an indication on the input conductor of said one crosspoint switching means that said input conductor is connected to an operated switching means of said second stage.

Claim 11

Dependent Claim 264 words

A multiple stage switching network comprising a plurality of cascaded stages, each stage being comprised of a plurality of matrices wherein each matrix comprises a plurality of input and output conductors intersecting at respective crosspoint elements of a single type, with each crosspoint element of each stage including a bistable switching device, said network having input devices individually coupled to respective input conductors of a first stage and output devices individually coupled to output conductors of a final stage, means in said network responsive to a first marking signal from an input device to an input conductor of said first stage and a second marking signal from an output device for initiating a search for an available path through the stages of said network, each such crosspoint switching device including a gate terminal and bias terminals, said search initiating means including allotting means for enabling successive gate terminals of crosspoints of the first stage coupled to the marked input conductor of said first stage to render one of said crosspoints in said first stage conductive on concurrence of the enabling of a crosspoint gate terminal and the presence of a first marking signal from the input device, means for enabling the gate terminals of crosspoints of said final stage and maintaining said crosspoints enabled during the entire path search to render crosspoints of said final stage conductive responsive to the second marking signal from said output device, and means for successively allotting gate terminals of an intermediate stage of the network to complete a path between conductive crosspoints of said first and final stages.

Claim 12

Dependent Claim 264 words

A multiple stage switching network comprising a plurality of cascaded stages, each stage being comprised of a plurality of matrices wherein each matrix comprises a plurality of input and output conductors intersecting at respective crosspoint elements of a single type, with each crosspoint element of each stage including a bistable switching device, said network having input devices individually coupled to respective input conductors of a first stage and output devices individually coupled to output conductors of a final stage, means in said network responsive to a first marking signal from an input device to an input conductor of said first stage and a second marking signal from an output device for initiating a search for an available path through the stages of said network, each such crosspoint switching device including a gate terminal and bias terminals, said search initiating means including allotting means for enabling successive gate terminals of crosspoints of the first stage coupled to the marked input conductor of said first stage to render one of said crosspoints in said first stage conductive on concurrence of the enabling of a crosspoint gate terminal and the presence of a first marking signal from the input device, means for enabling the gate terminals of crosspoints of said final stage and maintaining said crosspoints enabled during the entire path search to render crosspoints of said final stage conductive responsive to the second marking signal from said output device, and means for successively allotting gate terminals of an intermediate stage of the network to complete a path between conductive crosspoints of said first and final stages.

Claim 13

Dependent Claim 58 words

A network as claimed in claim 8, wherein said network includes a further intermediate stage, wherein the crosspoint switching devices of the network comprise thyristors and wherein a predetermined proportion of the thyristors of said further stage are enabled responsive to the conduction of a thyristor of said final stage to await path completion from said intermediate stage.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-10-21	1978-04-22	1978-10-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-10-21	1982-04-22	1982-10-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-10-21	1986-04-22	1986-10-22	$7700.00	Window Closed / Lapsed

Multiple stage telecommunications switching network

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