US3692949A — Multi-stage electronic switching network

Claim 1

Independent Claim 149 words

A switching network comprising a plurality of cascaded switching stages, each of said stages including an array of horizontal and vertical multiples with electronic crosspoints connected via respective first and second terminals across intersections of the multiples in the array, means coupling each vertical in one stage to a horizontal in a following stage, and timing means including a resistor-capacitor circuit connected to each of said vertical multiples and to the coupling means, the resistor-capacitor circuits coupled to the verticals in one stage each having substantially the same time constant, the resistorcapacitor circuits coupled to verticals in succeeding stages having successively longer time constants, said resistorcapacitor circuits accepting a charge when a cross-point coupled to an associated vertical conducts and providing a back-bias when the crosspoint quits conducting such that the crosspoint is prevented from conducting again after it turns off for periods proportional to the respective time constant.

Claim 2

Dependent Claim 149 words

A switching network comprising a plurality of cascaded switching stages, each of said stages including an array of horizontal and vertical multiples with electronic crosspoints connected via respective first and second terminals across intersections of the multiples in the array, means coupling each vertical in one stage to a horizontal in a following stage, and timing means including a resistor-capacitor circuit connected to each of said vertical multiples and to the coupling means, the resistor-capacitor circuits coupled to the verticals in one stage each having substantially the same time constant, the resistorcapacitor circuits coupled to verticals in succeeding stages having successively longer time constants, said resistorcapacitor circuits accepting a charge when a cross-point coupled to an associated vertical conducts and providing a back-bias when the crosspoint quits conducting such that the crosspoint is prevented from conducting again after it turns off for periods proportional to the respective time constant.

Claim 3

Dependent Claim 73 words

A switching network as claimed in claim 1, in which said resistor-capacitor circuits include a connection for the capacitor between the coupling means and ground and a connection for the resistor between the coupling means and a fixed potential, said capacitor charging directly when an associated crosspoint conducts and discharging through the resistor and ground circuit when the crosspoint is non-conductive to provide the back bias to inhibit thE crosspoint from conducting again.

Claim 4

Dependent Claim 128 words

An electronic switching network comprising a plurality of crosspoint stages connected in cascaded sequence, each crosspoint in a stage being connected to a plurality of crosspoints in the next cascaded stage, a timing means connected to a common terminal between each crosspoint and the next cascaded stage, said timing means including resistor-capacitor circuits, means coupling resistor-capacitor circuits having substantially the same time constant to each stage, each resistor-capacitor circuit coupled to a successive stage having a longer time constant, said timing means responding to signals from the associated crosspoint to develop a bias for controlling the turned-on time period of the crosspoint during a route search and providing a bias subsequently to inhibit said crosspoint from turning on again for a time period after having once turned off.

Claim 5

Dependent Claim 128 words

An electronic switching network comprising a plurality of crosspoint stages connected in cascaded sequence, each crosspoint in a stage being connected to a plurality of crosspoints in the next cascaded stage, a timing means connected to a common terminal between each crosspoint and the next cascaded stage, said timing means including resistor-capacitor circuits, means coupling resistor-capacitor circuits having substantially the same time constant to each stage, each resistor-capacitor circuit coupled to a successive stage having a longer time constant, said timing means responding to signals from the associated crosspoint to develop a bias for controlling the turned-on time period of the crosspoint during a route search and providing a bias subsequently to inhibit said crosspoint from turning on again for a time period after having once turned off.

Claim 6

Dependent Claim 110 words

A switching circuit as claimed in claim 3, including means for applying a firing end-marking voltage to one side of said network for repeatedly switching on the crosspoints in succeeding stages, said timing means being synchronized throughout said network so that crosspoints in succeeding stages turn on in a timed relationship to maximize the transfer of power from the end-marking voltage means through said network, and resistor means coupled to limit the current available from said end-marking means and thus to enable only a predetermined number of the available ones of said crosspoints to turn on throughout said cascaded stages, said predetermined number being less than said plurality of crosspoints.

Claim 7

Dependent Claim 102 words

An electronic crosspoint switching network comprising a plurality of cascaded stages of crosspoints providing a plurality of possible alternate paths extending through said network, each path being completed via a series circuit including a single crosspoint in each cascaded stage, said alternate paths being offered via other crosspoints coupled in parallel with each crosspoint in said series connection of crosspoints, and timing means coupled to a terminal between each series connected pair of crosspoints, said timing means including resistor-capacitor circuits providing the same time constant between crosspoints of one pair of stages and successively longer time constants between succeeding pairs of stages.

Claim 8

Dependent Claim 102 words

An electronic crosspoint switching network comprising a plurality of cascaded stages of crosspoints providing a plurality of possible alternate paths extending through said network, each path being completed via a series circuit including a single crosspoint in each cascaded stage, said alternate paths being offered via other crosspoints coupled in parallel with each crosspoint in said series connection of crosspoints, and timing means coupled to a terminal between each series connected pair of crosspoints, said timing means including resistor-capacitor circuits providing the same time constant between crosspoints of one pair of stages and successively longer time constants between succeeding pairs of stages.

Claim 9

Dependent Claim 71 words

A switching network as claimed in claim 5, in which means are included for applying a firing potential of limited power to one end of said series circuit for successively firing crosspoints in alternate paths in a sequence controlled by said timing means to conduct successive searches through said network, said power limitation precluding the firing of more than a predetermined number of crosspoints during any one of said successive searches.

Claim 10

Dependent Claim 36 words

The network of claim 5 wherein said predetermined number of crosspoints is no more than five out of at least nineteen crosspoints distributed over at least three cascaded stages in each possible path through said network.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1975-09-19	1976-03-20	1976-09-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1979-09-19	1980-03-20	1980-09-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1983-09-19	1984-03-20	1984-09-19	$7700.00	Window Closed / Lapsed

Multi-stage electronic switching network

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