Telephone subscriber line dial pulse detector circuit

Claim 2

In a telephone system, in combination, a plurality of subscriber lines each including a tip and ring conductor and each having a subset circuit including a hookswitch and dial contacts connected across one end of said tip and ring conductors, a transmission switching network comprising a plurality of pairs of conducting paths therethrough and a coordinate array of semiconductor cross-point devices for selectively defining said pairs of conducting paths; a plurality of first transformer means for coupling, respectively, the other ends of said tip and ring conductors to one end of said pairs of conducting paths, a plurality of detection circuits, and a plurality of second transformer means for coupling, respectively, said plurality of detection circuits to the other ends of said pairs of conducting paths, each of said detection circuits comprising a source of alternating current for applying an alternating sensing current to the subset circuits of said subscriber lines and means for measuring the magnitude of said sensing current when both said hookswitch and dial contacts are closed and when either said hookswitch contacts or said dial contacts are open.

Claim 3

A supervisory circuit arrangement for a telephone system having a transmission network including a coordinate array of semiconductor cross-point devices operable for selectively establishing a plurality of conducting paths between a first plurality of terminals of said network and a second plurality of terminals of said network and a plurality of subscriber lines each having a hookswitch and dial contacts therein, said subscriber lines being transformer-coupled respectively to said first plurality of terminals of said network, said supervisory circuit arrangement comprising a plurality of alternating current sources transformer-coupled respectively to said second plurality of terminals of said network for selectively aPplying an alternating sensing current through said network to selected lines of said plurality of subscriber lines, means associated with each of said plurality of alternating current sources for measuring the magnitude of said sensing current when both said hookswitch and said dial contacts of said selected lines are closed and when either said hookswitch or said dial contacts of said selected lines are open, and means associated with each of said plurality of alternating current sources for generating an output signal indicating the magnitude of said sensing current.

Claim 4

A supervisory circuit arrangement for a telephone system having a transmission network including a coordinate array of semiconductor cross-point devices operable for selectively establishing a plurality of conducting paths between a first plurality of terminals of said network and a second plurality of terminals of said network and a plurality of subscriber lines each having a hookswitch and dial contacts therein, said subscriber lines being transformer-coupled respectively to said first plurality of terminals of said network, said supervisory circuit arrangement comprising a plurality of alternating current sources transformer-coupled respectively to said second plurality of terminals of said network for selectively aPplying an alternating sensing current through said network to selected lines of said plurality of subscriber lines, means associated with each of said plurality of alternating current sources for measuring the magnitude of said sensing current when both said hookswitch and said dial contacts of said selected lines are closed and when either said hookswitch or said dial contacts of said selected lines are open, and means associated with each of said plurality of alternating current sources for generating an output signal indicating the magnitude of said sensing current.

Claim 5

In a telephone system, in combination, a plurality of subscriber lines each terminating at one end in a subset circuit including dial contacts, each of said lines presenting a predetermined impedance when said contacts are open, a transmission switching network comprising a coordinate array of semiconductor crosspoint elements for selectively defining a plurality of conducting paths therethrough between a first and a second plurality of terminals of said network, a plurality of transformer means for coupling, respectively, the other ends of said plurality of subscriber lines to said first plurality of terminals of said network, a source of alternating current for applying an alternating sensing current to a selected one of said second plurality of terminals terminating a selected one of said conducting paths through said network, and means for detecting the magnitude of said sensing current and for generating an output signal indicative of said magnitude when a subscriber line coupled to said selected conducting path presents said predetermined impedance.

Claim 6

In a telephone system, in combination, a plurality of subscriber lines each terminating at one end in a subset circuit including dial contacts, each of said lines presenting a predetermined impedance when said contacts are open, a transmission switching network comprising a coordinate array of semiconductor crosspoint elements for selectively defining a plurality of conducting paths therethrough between a first and a second plurality of terminals of said network, a plurality of transformer means for coupling, respectively, the other ends of said plurality of subscriber lines to said first plurality of terminals of said network, a source of alternating current for applying an alternating sensing current to a selected one of said second plurality of terminals terminating a selected one of said conducting paths through said network, and means for detecting the magnitude of said sensing current and for generating an output signal indicative of said magnitude when a subscriber line coupled to said selected conducting path presents said predetermined impedance.