Camp-on circuitry

Claim 2

Camp-on circuitry for use in a communication system having a plurality of line circuits and means for selectively applying an enabling signal to said circuits to determine the busy-idle call status of said circuits, and said circuitry comprising; means responsive to a receipt of a busy call status signal from a called one of said circuits for withdrawing said enabling signal from said circuits to ascertain the camp-on busy-idle status of said called one of said circuits, and busy control means subsequently responsive to a receipt of a camp-on busy status signal from said called one of said circuits for controlling a return of a supervisory busy signal to a calling station.

Claim 3

Camp-on circuitry in accordance with claim 1 wherein said busy control means includes means activated during an application of said enabling signal to said called one of said line circuits on an intercom call thereto and in response to a busy call status signal from said called one of said line circuitS for operating said busy control means on said intercom call prior to any withdrawing of said enabling signal from said circuits and to return a supervisory busy signal to a calling one of said line circuits.

Claim 4

Camp-on circuitry in accordance with claim 1 further comprising means operated upon a receipt of a camp-on idle status signal for examining each of said line circuits to identify said called one of said circuits, and means activated by said examining means for controlling a completion of camp-on call connections to an identified called one of said circuits.

Claim 5

Camp-on circuitry in accordance with claim 3 wherein said examining means includes a plurality of link circuits each of which is operably connectable to an individual one of said line circuits. a link scanner activated upon a receipt of a camp-on idle status signal on an inward terminating call for sequentially addressing each of said link circuits individually to operate said called one of said line circuits, and means responsive to a link circuit operation of said called one of said line circuits for deactivating said scanner and stopping scanner addressing at said called one of said line circuits.

Claim 6

Camp-on circuitry for a switching system having a plurality of line circuits, a switching network operable for establishing link connections on calls for said circuits, network control means responsive to a receipt of a call for any one of said circuits for operating said network to establish a link connection to the called line circuit, and means in said called line circuit subsequently responsive on another call for supplying a busy link connection signal, and said camp-on circuitry comprising a plurality of link circuits each of which is individually connected to one of said network link connections; a link scanner operable following a receipt of a busy link connection signal for sequentially activating said link circuits to supply a camp-on control signal to said called line circuit, and camp-on control means responsive to said control signal from said called line circuit for selectively cooperating with said network control means to control an operation said network for camp-on connecting said other call to said individual one of said link connections to said called line circuits.

Claim 7

Camp-on circuitry for a switching system having a plurality of line circuits, a switching network operable for establishing link connections on calls for said circuits, network control means responsive to a receipt of a call for any one of said circuits for operating said network to establish a link connection to the called line circuit, and means in said called line circuit subsequently responsive on another call for supplying a busy link connection signal, and said camp-on circuitry comprising a plurality of link circuits each of which is individually connected to one of said network link connections; a link scanner operable following a receipt of a busy link connection signal for sequentially activating said link circuits to supply a camp-on control signal to said called line circuit, and camp-on control means responsive to said control signal from said called line circuit for selectively cooperating with said network control means to control an operation said network for camp-on connecting said other call to said individual one of said link connections to said called line circuits.

Claim 8

Camp-on circuitry in accordance with claim 5 wherein a special supervisory signal is applied to link connections for a call camp-on connected thereto, and said called line circuit includes means responsive to said supervisory signal for generating a camp-on busy signal, and said camp-on circuitry further comprises logic circuit means responsive to a busy link connection signal and a camp-on busy signal for operating said network control means to return a supervisory busy signal on a subsequently received call.

Claim 9

Camp-on circuitry in accordance with claim 5 further comprising control circuit means for starting an operation of said link scanner and including a bistable switching device and gate means responsive on an inward terminating call to a receipt of a camp-on idle signal for activating said switching device and gate means to start said operation of said link scanner, and said camp-on control means includes a logic gate controlled by said activating of said switching device and a camp-on control signal from said called line circuit for stopping said operation of said link scanner.

Claim 10

Camp-on circuitry in accordance with claim 5 wherein said switching network comprises a crossbar switching network having a plurality of switch verticals for terminating functional switching circuits including said line circuits and a plurality of switch horizontals each of which provides link connections among said switch verticals. each of said link circuits is connected to an individual one of said switch horizontals, said link scanner successively activates said link circuits to supply said camp-on control signal through oNe of said crossbar switch horizontal and vertical link connections to said called line circuit, and means in said called line circuit for extending said camp-on control signal through said cross-bar switching network to said camp-on control means.

Claim 11

In a telephone system having a plurality of line circuits, a switching network operable for establishing link connections on calls for said circuits, common control means responsive to a receipt of a call for any one of said circuits for operating said network to establish a link connection to the called line circuit, and means in said called line circuit subsequently responsive to a receipt of another call for said called line circuit for producing busy connection signals for said one of said circuits, the improvement comprising means responsive to a busy signal from said called line circuit for controlling said producing means to generate a camp-on idle signal, a plurality of link circuits each of which is connected to an individual one of said link connections of said network, circuit means responsive to said camp-on idle signal for said called line circuit for sequentially operating each of said link circuits selectively to mark each of said link connections, means responsive to a marking of said link connection connected to said called line circuit for providing and identification signal through said called line circuit to identify said last-mentioned link connection, and means in said common control means responsive to said identifying signal for controlling an operation of said network to camp-on connect said other call on said link connection connected to said called line circuit.

Claim 12

In a telephone system having a plurality of line circuits, a switching network operable for establishing link connections on calls for said circuits, common control means responsive to a receipt of a call for any one of said circuits for operating said network to establish a link connection to the called line circuit, and means in said called line circuit subsequently responsive to a receipt of another call for said called line circuit for producing busy connection signals for said one of said circuits, the improvement comprising means responsive to a busy signal from said called line circuit for controlling said producing means to generate a camp-on idle signal, a plurality of link circuits each of which is connected to an individual one of said link connections of said network, circuit means responsive to said camp-on idle signal for said called line circuit for sequentially operating each of said link circuits selectively to mark each of said link connections, means responsive to a marking of said link connection connected to said called line circuit for providing and identification signal through said called line circuit to identify said last-mentioned link connection, and means in said common control means responsive to said identifying signal for controlling an operation of said network to camp-on connect said other call on said link connection connected to said called line circuit.

Claim 13

The improvement of claim 9 further comprising means activating said called line circuit for applying a camp-on busy signal through said network to said common control means on an inward terminating call, and busy control means responsive to said camp-on busy signal for operating said common control means to preclude camp-on connections through said network to said called line circuit for said terminating call.

Claim 14

The improvement of claim 10 wherein said busy control means includes logic means responsive to a receipt of a busy connection signal followed by a camp-on busy signal from said called line circuit for supplying a camp-on busy command to said common control means.

Claim 15

The improvement of claim 11 wherein said logic means comprises a logic arrangement responsive to a receipt of a busy connection signal via said network from said called line circuit for controlling an examination of the camp-on busy-idle status of said link connection to said called line circuit, and logic circuit means including a delay device responsive to a camp-on busy status signal through said network from said called line circuit for supplying said camp-on busy command to said common control means.

Claim 16

The improvement of claim 12 wherein said logic arrangement includes a bistable flip-flop, and gate means responsive to coincident receipt of signals including inward terminating call and busy connection signals for operating said flip-flop for controlling via said called line circuit an examination of said camp-on busy-idle status of said link connection to said called line circuit.

Claim 17

The improvement of claim 13 wherein said logic circuit means includes gate circuitry controlled by said delay device and flip-flop for supplying a camp-on busy tone command to said common control means.

Claim 18

The improvement of claim 9 wherein said circuit means includes a link scanner activatable for sequentially operating said link circuits selectively to mark each of link connections, a logic circuit responsive to said camp-on idle signal from said called line circuit for activating said link scanner, said called line circuit being responsive to a marking of said link connection connected thereto for applying said link identification signal through said network, and a control gate arrangement controlled by a receipt of said identification signal from said network for deactivating said link scanner.

Claim 19

The improvement of claim 15 wherein said logic circuit includes a bistable switching device, and a gate circuit responsive to a receipt of a camp-on idle signal for operating said switching device to commence an activation of said link scanner and thereby operating said link circuits sequentially to mark each of said link connections.

Claim 20

The improvement of claim 9 further comprising intercom control means responsive to a receipt of a busy connection signal from said called line circuit on an intercom call for operating said common control means to preclude camp-on connections of said intercom call through said network link connection to said called line circuit.

Claim 21

The improvement of claim 17 wherein said intercom control means includes gate means responsive to a coincident receipt of said busy connection signal from said called line circuit on said intercom call and an intercom call identifying signal for supplying a busy tone command to said common control means.

Claim 22

A private branch exchange telephone system comprising a plurality of line circuits, a crossbar switching network having a plurality of switch verticals for terminating functional switching circuits including said line circuits and a plurality of switch horizontals each of which provides link connections among said switch verticals, common control means responsive to a receipt of a terminating call for any one of said circuits for operating said network to establish a link connection to the called line circuit, a plurality of link circuits each one of which is connected to an individual one of said network link connections and being addressable for marking an individual one of said link connections for identification, said common control means including means responsive to another terminating call for addressing said called line circuit to determine a busy status of the network link connection connected thereto, means responsive to a busy status of said last-mentioned link connection for controlling each of said line circuits to ascertain the camp-on busy-idle status of said called line circuit, means responsive to a camp-on busy status signal from said called line circuit via said network for generating a busy tone command for said other terminating call, means responsive to a camp-on idle status signal from said called line circuit via said network for sequentially addressing each of said link circuits for marking said link connection connected to said called line circuit, said called line circuit including means responsive to said last-mentioned link connection marking for sending a link connection identifying signal to said common control means via said network, and means in said common control means responsive to said identifying signal for arresting further addressing of said link circuits and generating a network command for camp-on connection of said other terminating call to said network link connection to said called line circuit.

Claim 23

A private branch exchange telephone system comprising a plurality of line circuits, a crossbar switching network having a plurality of switch verticals for terminating functional switching circuits including said line circuits and a plurality of switch horizontals each of which provides link connections among said switch verticals, common control means responsive to a receipt of a terminating call for any one of said circuits for operating said network to establish a link connection to the called line circuit, a plurality of link circuits each one of which is connected to an individual one of said network link connections and being addressable for marking an individual one of said link connections for identification, said common control means including means responsive to another terminating call for addressing said called line circuit to determine a busy status of the network link connection connected thereto, means responsive to a busy status of said last-mentioned link connection for controlling each of said line circuits to ascertain the camp-on busy-idle status of said called line circuit, means responsive to a camp-on busy status signal from said called line circuit via said network for generating a busy tone command for said other terminating call, means responsive to a camp-on idle status signal from said called line circuit via said network for sequentially addressing each of said link circuits for marking said link connection connected to said called line circuit, said called line circuit including means responsive to said last-mentioned link connection marking for sending a link connection identifying signal to said common control means via said network, and means in said common control means responsive to said identifying signal for arresting further addressing of said link circuits and generating a network command for camp-on connection of said other terminating call to said network link connection to said called line circuit.