Telephone system employing electronic matrix

Claim 2

A telephone intercommunication system comprising a plurality of stations, a line circuit individual to each station, a conversation link circuit interposed between line circuits of a calling one and a called one of said stations to complete a conversation path between said stations through a switching network, a Current source of like polarity individual to each line circuit, a ground connection intermediately within a completed conversation path, and commonly connected to both calling and called stations, means associated with each current source for providing a constant current output to said conversation path from each said source, and means for sensing the current from said sources to determine the idle or busy condition of stations connected to said conversation path.

Claim 3

A system as claimed in claim 1, wherein said ground connection includes a choke coil for filtering alternating currents from said ground connection, and there are direct current sensing means in said common ground connection for supervising said conversation path.

Claim 4

A system as claimed in claim 1, further comprising means in said link circuit responsive to a predetermined value of current received from both the calling and called stations for maintaining said conversation path intact, and further means in said link circuit for detecting current from only one of said stations to initiate the release of both the called and calling stations from said conversation path.

Claim 5

A multi-station telephone intercommunication system comprising a single-stage, switching matrix for finding a calling one of the stations and for connecting to a called one of the stations, said matrix comprising a plurality of intersecting bus multiples with an identical crosspoint at each multiple intersection, each of said busses of a first of said multiples representing one of said stations, each crosspoint including a first switching member responsive to a signal from the calling station represented by the bus of the calling station for switching a line from the calling station through said matrix to an intermediate member and each crosspoint including a second switching member for controlling the switching through of a path between said calling station and a called station during a ringing interval and for switching control of the connection to said first switching member on response of the called station, each said switching member comprising a transistor, and each crosspoint further including means for maintaining that crosspoint connected to a calling station and another crosspoint connected to a called station in a call completing condition, and means for detecting the release of said calling station to restore both crosspoints from the call completing condition.

Claim 6

A multi-station telephone intercommunication system comprising a single-stage, switching matrix for finding a calling one of the stations and for connecting to a called one of the stations, said matrix comprising a plurality of intersecting bus multiples with an identical crosspoint at each multiple intersection, each of said busses of a first of said multiples representing one of said stations, each crosspoint including a first switching member responsive to a signal from the calling station represented by the bus of the calling station for switching a line from the calling station through said matrix to an intermediate member and each crosspoint including a second switching member for controlling the switching through of a path between said calling station and a called station during a ringing interval and for switching control of the connection to said first switching member on response of the called station, each said switching member comprising a transistor, and each crosspoint further including means for maintaining that crosspoint connected to a calling station and another crosspoint connected to a called station in a call completing condition, and means for detecting the release of said calling station to restore both crosspoints from the call completing condition.

Claim 7

A system as claimed in claim 4, wherein said first switching member has its emitter and collector connected to a speech path lead of said line, and each said second switching member is connected to a control lead of said line.

Claim 8

A telephone intercommunication system comprising a plurality of stations, a source of constant current of like polarity individual to each of said stations, a conversation link circuit interposed between a calling one and a called one of said stations to complete a conversation path between said stations, means in said link circuit responsive to the activation of said link circuit for completing a connection common to both stations in said conversation path, supervisory control means in said last-mentioned connection for sensing the amount of current from the stations connected to said conversation path for monitoring the idle or busy condition of the stations in the conversation path.

Claim 9

A telephone intercommunication system comprising a plurality of stations, a source of constant current of like polarity individual to each of said stations, a conversation link circuit interposed between a calling one and a called one of said stations to complete a conversation path between said stations, means in said link circuit responsive to the activation of said link circuit for completing a connection common to both stations in said conversation path, supervisory control means in said last-mentioned connection for sensing the amount of current from the stations connected to said conversation path for monitoring the idle or busy condition of the stations in the conversation path.

Claim 10

A system as claimed in claim 6, wherein said common connection includes a choke coil interposed between said conversation path and said supervisory means for isolating said sensing means from any alternating current received from said stations in the conversation path.

Claim 11

A system as claimed in claim 6, comprising means in said link circuit responsive to a predetermined value of current received from both the calling and called stations for maintaining said conversation path intact, and further means in said link circuit for detecting a predetermined value of current from only one of said stations to initiate the opening of said converSation path.

Claim 12

A telephone system comprising a single stage electronic matrix for completing calls from a calling station at one side of said matrix to a link circuit at the other side of said matrix, and from said link circuit to a called station at the one side of said matrix, said matrix comprising a plurality of crosspoints each having a connection to one of said stations and connectable to said link circuit, each said crosspoint comprising a first switching member, the invention comprising means for firing the first switching member of the cross-point connected to a calling station and said connected link circuit to initiate a connection from said calling station to said link circuit, and a second switching member in the crosspoint connected to said calling station, said second switching member responsive to a called station being idle for latching said crosspoint.

Claim 13

A telephone system comprising a single stage electronic matrix for completing calls from a calling station at one side of said matrix to a link circuit at the other side of said matrix, and from said link circuit to a called station at the one side of said matrix, said matrix comprising a plurality of crosspoints each having a connection to one of said stations and connectable to said link circuit, each said crosspoint comprising a first switching member, the invention comprising means for firing the first switching member of the cross-point connected to a calling station and said connected link circuit to initiate a connection from said calling station to said link circuit, and a second switching member in the crosspoint connected to said calling station, said second switching member responsive to a called station being idle for latching said crosspoint.

Claim 14

A system as claimed in claim 9, wherein there is means in said link circuit connected to said second switching member for controlling the maintenance of the latching of said crosspoint.

Claim 15

A system as claimed in claim 10, wherein the first switching member of the crosspoint connected to the called station is rendered conductive responsive to a call being directed to said called station, and the second switching member of the crosspoint connected to the called station responsive to the called station answering the call for latching said last mentioned crosspoint under the control of control means in said link circuit.

Claim 16

A system as claimed in claim 11, wherein said switching members of a crosspoint each comprise a transistor connected in complementary flip-flop arrangement.