Path finding system for a multi-stage switching network

Claim 2

A path finding system for effecting interconnection of circuits through a switching network, wherein the network includes at least three matrix stages interconnected by links to provide plural paths between circuits connected to opposite ends of the network, and wherein each stage is divided into separate matrix groups, said path finding system comprising: means for selectively marking circuits connected to matrix groups in the stages at opposite ends of the network; switching means in the plurality of matrix groups in at least two stages that are separated by at least one stage, for providing signals designating the busy-free condition of the individual link interconnections to the matrix groups in said two stages; detection means sequentially scanning the individual link interconnections to matrix groups in one of said two stages and simultaneously therewith scanning the corresponding link interconnections to matrix groups in the other one of said stages, so that the busy-free condition of the link interconnections that form separate paths through the network for interconnecting said marked circuits are sequentially scanned, and circuit means, responsive to the simultaneous detection of a free condition of link interconnections to each of said two stages defining a free path through the network between marked circuits, for completing the connection through the network including the free path.

Claim 3

A path finding system as defined in claim 1 wherein said circuit means includes: a plurality of groups of switch means, a separate group of switch meanS for each of the matrix groups in one of said two stages, and wherein separate ones of said switch means in said plurality of groups are connected in series with individual ones of said link interconnections to the matrix groups in said one stage; means for sequentially applying enabling signals synchronized to said detection means to a selected group of switch means at a rate wherein said switch means do not respond to said enabling signals, and means for stopping said applying means when a free path is detected so that an enabling signal is applied to said switch means in said free path for a sufficient period of time to complete a connection through the network between marked circuits at opposite ends of said network.

Claim 4

A path finding system as defined in claim 1 wherein said circuit means includes: a plurality of groups of switch means, a separate group of switch means for each of the matrix groups in one of said two stages, and wherein separate ones of said switch means in said plurality of groups are connected in series with individual ones of said link interconnections to the matrix groups in said one stage; means for sequentially applying a first signal synchronized to said detection means to a selected group of switch means; means for stopping said first signal applying means when a free path is detected so that said first signal applying means applies a continuous signal to the switch means in said free path, and means for applying a second signal to the switch means in said free path when said first signal applying means is stopped so that said switch means in said free path is actuated by the simultaneous presence of said first and second signals to complete a connection between marked circuits on opposite ends of said network.

Claim 5

A path finding system as defined in claim 1 wherein: the network includes first and second matrix stages separated by a third matrix stage; said switching means are included in said first and second stages, and said detection means is connected to the switching means in said first and second stages.

Claim 6

A path finding system as defined in claim 4 wherein: said switching means are included in the third matrix stage and are interconnected to the switching means in the first and second matrix stages to correspond with the paths through said first, second and third matrix stages.

Claim 7

A path finding system for effecting interconnection of circuits through a switching network, wherein said network includes at least three switching matrix stages interconnected to provide plural control paths and corresponding plural switch paths between circuits connected to opposite ends of the network, wherein each stage is divided into a plurality of separate matrix groups, and wherein each matrix group includes a plurality of crosspoint switching devices arranged to form a matrix switch with the crosspoint devices connected in the control paths and their switches connected in said switch paths, said path finding system comprising: means for selectively marking the control path interconnections of the circuits at opposite ends of the network; first switching means in the plurality of matrix groups in at least two stages that are separated by at least one stage, for providing signals designating the busy-free condition of control path interconnections to the matrix groups in said two stages; second switching means connected in series with the control path interconnections to matrix groups of one of said two stages; means for selecting the matrix groups in said two stages that include paths for interconnecting said marked circuits at opposite ends of said network; detecting means sequentially scanning the signals provided by the first switching means in the selected matrix groups in one of the two stages and simultaneously therewith sequentially scanning the signals provided by said first switching means in the selected matrix groups in the other one of said two stages, so That the busy-free condition of the pairs of the control path interconnections that define separate control paths through the network for interconnecting said marked circuits are sequentially detected, and circuit means responsive to said detecting means for actuating said second switching means in a detected free control path to complete a connection through the network via the two free control path interconnections that define the free control path.

Claim 8

A path finding system for effecting interconnection of circuits through a switching network, wherein said network includes at least three switching matrix stages interconnected to provide plural control paths and corresponding plural switch paths between circuits connected to opposite ends of the network, wherein each stage is divided into a plurality of separate matrix groups, and wherein each matrix group includes a plurality of crosspoint switching devices arranged to form a matrix switch with the crosspoint devices connected in the control paths and their switches connected in said switch paths, said path finding system comprising: means for selectively marking the control path interconnections of the circuits at opposite ends of the network; first switching means in the plurality of matrix groups in at least two stages that are separated by at least one stage, for providing signals designating the busy-free condition of control path interconnections to the matrix groups in said two stages; second switching means connected in series with the control path interconnections to matrix groups of one of said two stages; means for selecting the matrix groups in said two stages that include paths for interconnecting said marked circuits at opposite ends of said network; detecting means sequentially scanning the signals provided by the first switching means in the selected matrix groups in one of the two stages and simultaneously therewith sequentially scanning the signals provided by said first switching means in the selected matrix groups in the other one of said two stages, so That the busy-free condition of the pairs of the control path interconnections that define separate control paths through the network for interconnecting said marked circuits are sequentially detected, and circuit means responsive to said detecting means for actuating said second switching means in a detected free control path to complete a connection through the network via the two free control path interconnections that define the free control path.

Claim 9

A path finding system as defined in claim 6 including: means for stopping the detecting means when the free control path interconnections are detected, and means for restarting said detecting means after a preset period of time.

Claim 10

A path finding system as defined in claim 6 wherein said circuit means includes: scanning means for applying sequential scanning signals, in synchronism with said detecting means, to said second switching means of a time duration that is sufficient to permit the enabling of said second switching means, and circuit means for stopping said scanning means when a free control path is detected and wherein a scan signal of sufficient duration is applied to the second switch means in the free control path to switch the cross-point devices and complete the free path.

Claim 11

A path finding system as defined in claim 6 including: means for stopping said detecting means when signals indicating a free control path have been detected, and means applying a switching signal to said second switching means when said detecting means is stopped so that said second switching means in a control path interconnection of said free control path is actuated to complete the connection through the network.

Claim 12

A path finding system as defined in claim 6 wherein: the network includes first and second matrix stages separated by a third matrix stage; said first switching means are included in said first and second stages, and said detecting means is connected to the first switching means in said first and second stages.

Claim 13

A path finding system as defined in claim 10 wherein: said first switching means are included in the third matrix stage and are interconnected to the first switching means in the first and second matrix stages to correspond with the control paths through said first, second and third matrix stages.

Claim 14

A path finding system for effecting interconnection of telephone circuits through a switching network wherein said network includes at least three switching matrix stages wherein each stage is divided into separate matrix groups, wherein each matrix group includes a plurality of crosspoint devices arranged to form a matrix switch, and wherein the crosspoint devices in the matrix groups are interconnected between matrix groups of adjacent stages by control leads for controlling the actuation of said crosspoint devices to provide plural paths between telephone circuits connected to opposite ends of said network, said path finding system comprising: means for selectively marking the control leads of telephone circuits connected to matrix groups in the stages at opposite ends of said network; first switching means in the plurality of matrix groups in at least two stages that are separated by at least one stage for providing signals designating the busy-free condition of the control lead interconnections between the matrix groups in said two stages and the matrix groups of the stages adjacent said two stages; circuit means for selecting the matrix groups in said two stages including control path interconnections for completing paths between said marked telephone circuits; second switching means in series with the control lead interconnections between the matrix groups in one of said two stages and the matrix groups of an adjacent stage; scanning means for sequentially enabling the second switching means between the selected matrix groups in said one of said two stages for a time duration insufficient to enable the second switching means to switch the cross-point devices, and means synchronized with said scanning means for simultaneously detecting a signal from a matrix group in both of said two stages indicating a free condition in a control lead interconnection through the network and for stopping said scanning means so that second switching means in one of the detected free control lead interconnections is enabled for a sufficient time duration to switch crosspoint devices in said plurality of stages to complete the control path between marked telephone circuits on opposite ends of said network.

Claim 15

A path finding system for effecting interconnection of telephone circuits through a switching network wherein said network includes at least three switching matrix stages wherein each stage is divided into separate matrix groups, wherein each matrix group includes a plurality of crosspoint devices arranged to form a matrix switch, and wherein the crosspoint devices in the matrix groups are interconnected between matrix groups of adjacent stages by control leads for controlling the actuation of said crosspoint devices to provide plural paths between telephone circuits connected to opposite ends of said network, said path finding system comprising: means for selectively marking the control leads of telephone circuits connected to matrix groups in the stages at opposite ends of said network; first switching means in the plurality of matrix groups in at least two stages that are separated by at least one stage for providing signals designating the busy-free condition of the control lead interconnections between the matrix groups in said two stages and the matrix groups of the stages adjacent said two stages; circuit means for selecting the matrix groups in said two stages including control path interconnections for completing paths between said marked telephone circuits; second switching means in series with the control lead interconnections between the matrix groups in one of said two stages and the matrix groups of an adjacent stage; scanning means for sequentially enabling the second switching means between the selected matrix groups in said one of said two stages for a time duration insufficient to enable the second switching means to switch the cross-point devices, and means synchronized with said scanning means for simultaneously detecting a signal from a matrix group in both of said two stages indicating a free condition in a control lead interconnection through the network and for stopping said scanning means so that second switching means in one of the detected free control lead interconnections is enabled for a sufficient time duration to switch crosspoint devices in said plurality of stages to complete the control path between marked telephone circuits on opposite ends of said network.

Claim 16

A path finding system as defined in claim 12 wherein: the crosspoint devices comprise relay switches having mark and sleeve relay coils, wherein the mark coils are interconnected by said control leads, wherein said sleeve coils are interconnected by sleeve leads and by contacts of their respective relay switches to form plural hold current paths, and wherein other contacts of said relay switches are interconnected to form plural signal paths, and said first switching means comprise a separate contact from each of said relay switches in each of said matrix groups in said two stages, and wherein the contacts are interconnected in the matrix groups in each matrix stage to provide separate busy-free signals for each of the control lead interconnections to said matrix groups in said two stages and so that when one of the relays connected to a control lead interconnection is activated, the contacts of the activated relay provide a busy signal for that control lead interconnection.

Claim 17

A path finding system as defined in claim 12 wherein: the network includes first and second matrix stages separated by a third matrix stage; said first switching means is included in said first and second stages, and said detecting means is connected to the switching means in said first and second stages.

Claim 18

A path finding system as defined in claim 14 wherein: said first switching means are included in the third matrix stage and are interconnected to the first switching means in the first and second matrix stages to correspond with the paths through said first, second and third matrix stages.

Claim 19

A path finding system for effecting interconnection of circuits through a switching network, wherein said network includes at least three matrix stages interconnected to provide plural paths between circuits connected to opposite ends of said network, and wherein each stage is divided into separate matrix groups, said path finding system comprising: means for selectively marking circuits connected to matrix groups in the stages at opposite ends of the network; switching means in the plurality of matrix groups in two stages at the opposite ends of said network for providing signals designating the busy-free condition of individual interconnections between the matrix groups and the matrix groups of an adjacent stage; detection means sequentially scanning the individual interconnections to matrix groups in one of said end stages connected to a marked circuit and simultaneously therewith sequentially scanning the corresponding individual interconnections to a matrix group in the other one of said end stages, connected to a marked circuit, so that the busy-free condition of the individual interconnections that form separate paths through the network for interconnecting the marked circuits are sequentially scanned, and circuit means responsive to the simultaneous detection of a free condition in an interconnection to the matrix groups in both of said end stages for enabling the interconnections to complete a path through said network between marked circuits connected to opposite ends of said network.

Claim 20

A path finding system for effecting interconnection of circuits through a switching network, wherein said network includes at least three matrix stages interconnected to provide plural paths between circuits connected to opposite ends of said network, and wherein each stage is divided into separate matrix groups, said path finding system comprising: means for selectively marking circuits connected to matrix groups in the stages at opposite ends of the network; switching means in the plurality of matrix groups in two stages at the opposite ends of said network for providing signals designating the busy-free condition of individual interconnections between the matrix groups and the matrix groups of an adjacent stage; detection means sequentially scanning the individual interconnections to matrix groups in one of said end stages connected to a marked circuit and simultaneously therewith sequentially scanning the corresponding individual interconnections to a matrix group in the other one of said end stages, connected to a marked circuit, so that the busy-free condition of the individual interconnections that form separate paths through the network for interconnecting the marked circuits are sequentially scanned, and circuit means responsive to the simultaneous detection of a free condition in an interconnection to the matrix groups in both of said end stages for enabling the interconnections to complete a path through said network between marked circuits connected to opposite ends of said network.

Claim 21

A path finding system as defined in claim 16 wherein said circuit means includes: switch means connected in series with individual ones of said interconnections to the matrix groups in one of said end stages; scanning means foR sequentially applying enabling signals synchronized to said detection means to the switch means connected in series with the interconnections to said matrix groups of said one end stage connected to a marked circuit at a rate wherein said switch means do not respond to said signal, means for stopping scanning when a free path is detected for applying an enabling signal of sufficient duration to the switch means in said free path to complete a connection between marked devices on opposite ends of said network.

Claim 22

A path finding system as defined in claim 16 wherein said circuit means includes: switch means connected in series with individual ones of said interconnections to the matrix groups in one of said end stages; scanning means for sequentially applying first partial enabling signals synchronized to said detection means to said switch means; means for stopping said scanning means when the free path is detected, and means for applying a second partial enable signal to the switch means connected in series with the interconnections to the matrix group in said one end stage connected to a marked circuit after said scanning means is stopped so that said switch means is actuated by the simultaneous presence of said first and second signals to complete a path between marked circuits on opposite ends of said network.

Claim 23

A path finding system for effecting interconnection of circuits through a switching network, wherein the network includes a plurality of matrix stages interconnected by links to provide plural paths between circuits connected to opposite ends of the network, and wherein each stage is divided into separate matrix groups, said path finding system comprising: means for selectively marking circuits connected to matrix groups in the stages at opposite ends of the network; first switching means in the plurality of matrix groups in a first stage for providing signals designating the busy-free condition of individual link interconnections to the matrix groups; second switching means in the plurality of matrix groups in a second stage for providing signals designating the busy-free condition of individual link interconnections to the matrix groups; a first group of link check circuits, one for each of the matrix groups in said first stage, coupled to individual ones of said matrix groups in said first stage for monitoring the busy-free signals from said first switching means; a second group of link check circuits, one for each of the matrix groups in said second stage, coupled to individual ones of said matrix groups in said second stage for monitoring the busy-free signals from said second switching means; a plurality of groups of switching means, one group for each of the matrix groups in the first stage, wherein separate switching means are connected in series with individual ones of the link interconnections to the matrix groups of said first stage; first circuit means, responsive to the marking of the circuits connected to one end of the network, for selectively enabling ones of said first groups of link check circuits that monitor first stage matrix groups having link interconnections forming a portion of paths through the network to the marked circuits, and for enabling corresponding ones of said groups of switching means; second circuit means, responsive to the marking of the circuits connected to the other end of the network, for selectively enabling ones of said second groups of link check circuits that monitor second stage matrix groups having link interconnections forming a portion of paths through the network to the marked circuits; counting circuit means for providing a series of sequential scanning pulses; third circuit means coupled to apply the scanning pulses to said first and second groups of link check circuits so that the link check circuits enabled by said first and second means, respectively, simultaneously scan the busy-free condition of the link interconnections to the corresponding matrix groups; fourth circuit means for stopping said counting circuit means in response to a simultaneous free condition signal from the first and second enabled link check circuits; fifth circuit means for applying said scanning signals to the groups of switching means enabled by said first circuit means so that the switching means in the detected free path is enabled when said counting circuit means is stopped, and circuit means for restarting said counting circuit means.

Claim 24

A path finding system for effecting interconnection of circuits through a switching network, wherein the network includes a plurality of matrix stages interconnected by links to provide plural paths between circuits connected to opposite ends of the network, and wherein each stage is divided into separate matrix groups, said path finding system comprising: means for selectively marking circuits connected to matrix groups in the stages at opposite ends of the network; first switching means in the plurality of matrix groups in a first stage for providing signals designating the busy-free condition of individual link interconnections to the matrix groups; second switching means in the plurality of matrix groups in a second stage for providing signals designating the busy-free condition of individual link interconnections to the matrix groups; a first group of link check circuits, one for each of the matrix groups in said first stage, coupled to individual ones of said matrix groups in said first stage for monitoring the busy-free signals from said first switching means; a second group of link check circuits, one for each of the matrix groups in said second stage, coupled to individual ones of said matrix groups in said second stage for monitoring the busy-free signals from said second switching means; a plurality of groups of switching means, one group for each of the matrix groups in the first stage, wherein separate switching means are connected in series with individual ones of the link interconnections to the matrix groups of said first stage; first circuit means, responsive to the marking of the circuits connected to one end of the network, for selectively enabling ones of said first groups of link check circuits that monitor first stage matrix groups having link interconnections forming a portion of paths through the network to the marked circuits, and for enabling corresponding ones of said groups of switching means; second circuit means, responsive to the marking of the circuits connected to the other end of the network, for selectively enabling ones of said second groups of link check circuits that monitor second stage matrix groups having link interconnections forming a portion of paths through the network to the marked circuits; counting circuit means for providing a series of sequential scanning pulses; third circuit means coupled to apply the scanning pulses to said first and second groups of link check circuits so that the link check circuits enabled by said first and second means, respectively, simultaneously scan the busy-free condition of the link interconnections to the corresponding matrix groups; fourth circuit means for stopping said counting circuit means in response to a simultaneous free condition signal from the first and second enabled link check circuits; fifth circuit means for applying said scanning signals to the groups of switching means enabled by said first circuit means so that the switching means in the detected free path is enabled when said counting circuit means is stopped, and circuit means for restarting said counting circuit means.

Claim 25

A path finding system as defined in claim 19 wherein: said counting circuit means, when stopped, provides a continuous signal corresponding to the scanning pulse at which the counting means is stopped, and said fifth circuit means is responsive to a signal from the fourth circuit means to apply the continuous signal from said counting circuit means to said switching means enabled by said first circuit means to activate the switching means and complete the path through the network.

Claim 26

A path finding system as defined in claim 19 wherein: said counting circuit means provides said scanning signals at a sufficiently rapid repetition rate so that said switching means do not respond to the scanning signal from said counting circuit means until the counting circuit means is stopped.

Claim 27

A path finding system for effecting interconnection of circuits through a switching network, wherein said network includes at least three matrix stages interconnected to provide plural control paths and plural holding paths between circuits connected to opposite ends of the network, wherein each stage is divided into a plurality of separate matrix groups, wherein each matrix group includes a plurality of crosspoint relays arranged to form a matrix switch, and wherein each relay includes a hold winding connected in series with contacts of the relay and includes a control winding, with the control windings of each relay being connected in the control paths, and the hold windings of each relay being connected through the series contacts in corresponding holding paths, said path finding system comprising: means for selectively marking circuits connected to the matrix groups in the stages at opposite ends of the network; detection means simultaneously scanning the individual holding path connections to matrix groups in at least two stages that are separated by at least one stage and that include paths for interconnecting the marked circuits, for detecting the busy-free condition thereof, and circuit means, responsive to the simultaneous detection of free holding path connections to each of said two stages defining a free path through the network between marked circuits, for completing the inter-connection through the network including the free path.

Claim 28

A path finding system for effecting interconnection of circuits through a switching network, wherein said network includes at least three matrix stages interconnected to provide plural control paths and plural holding paths between circuits connected to opposite ends of the network, wherein each stage is divided into a plurality of separate matrix groups, wherein each matrix group includes a plurality of crosspoint relays arranged to form a matrix switch, and wherein each relay includes a hold winding connected in series with contacts of the relay and includes a control winding, with the control windings of each relay being connected in the control paths, and the hold windings of each relay being connected through the series contacts in corresponding holding paths, said path finding system comprising: means for selectively marking circuits connected to the matrix groups in the stages at opposite ends of the network; detection means simultaneously scanning the individual holding path connections to matrix groups in at least two stages that are separated by at least one stage and that include paths for interconnecting the marked circuits, for detecting the busy-free condition thereof, and circuit means, responsive to the simultaneous detection of free holding path connections to each of said two stages defining a free path through the network between marked circuits, for completing the inter-connection through the network including the free path.

Claim 29

A path finding system as defined in Claim 22 wherein said circuit means includes: a plurality of groups of switch means, a separate group of switch means for each of the matrix groups in one of said two stages, and wherein separate ones of said switch means in said plurality of groups are connected in series with individual ones of said control path connections to the matrix groups in said one stage; means for sequentially applying enabling signals synchronized to said sequential detecting means to a selected group of switch means included in control paths for interconnecting the marked circuits at a rate insufficient to permit enabling of said switch means, and means for stopping said applying means when a free path is detected so that an enabling signal is applied to said switch means in the control path of a detected free path for a sufficient period of time to complete a connection through the network between marked circuits at opposite ends of said network.

Claim 30

A path finding system as defined in claim 22 wherein said circuit means includes: a plurality of groups of switch means, a separate group of switch means for each of the matrix groups in one of said two stageS, and wherein separate ones of said switch means in said plurality of groups are connected in series with individual ones of said control path connections to the matrix groups in said one stage; means for sequentially applying first signals synchronized to said sequential detecting means to a selected group of switch means included in control paths for interconnecting the marked circuits; means for stopping said first signal applying means when a free path is detected so that said first signal applying means applies a continuous signal to the switch means in the control path of said detected free path, and means for applying second signals to the switch means in said free path when said first signal applying means is stopped so that said switch means in said detected free path is actuated by the simultaneous presence of said first and second signals to complete a connection between marked circuits on opposite ends of said network.