Multi-line telephone set with switching capability

Claim 2

A multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of line termination circuits for providing transmit and receive paths for each of a plurality of lines connected to said termination circuits, seize means operatively associated with a first one of said line termination circuits for connecting the transmit and receive paths of a first one of said lines to the transmit and receive paths of said local line circuit, hold means associated with said first line termination circuit including hold switch means operable when enabled to establish a D.C. supervision loop for said first line and a hold latch flip flop, said hold latch flip flop being set by said seize means to provide an enabling signal for said hold switch means in response to operation of said seize means to connect the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit, means in said multi-line telephone set for controlling said seize means to effect the connection of the transmit and receive paths of a second one of said lines to the transmit and receive paths of said local line circuit and to simultaneously disconnect the transmit and receive paths of said first line from the transmit and receive paths of said local line circuit without interrupting the D.C. supervision loop established for said first line whereby said first line is automatically placed in a hold condition, and release means operable to provide a signal for resetting said hold latch flip flop to disable said hold switch means thereby removing the hold condition from said first line whereby unintentional release of said first line cannot occur.

Claim 3

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a pluraLity of four-wire lines connected to said termination circuits, seize means operatively associated with said first line termination circuit for seizing a first one of said lines including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit, hold means associated with said first line termination circuit including hold switch means operable when enabled to establish a D.C. supervision loop for said first line and a hold latch flip flop, said hold latch flip flop being set by said seize means to provide an enabling signal for said hold switch means in response to operation of said seize means to seize said first line, means in said multi-line telephone set for controlling said seize means to connect the transmit and receive paths of a second one of said lines to said local line circuit and to simultaneously disconnect the transmit and receive paths of said first line from said local line circuit without disabling the hold switch means for said first line whereby said first line is automatically placed in a hold condition, and release means operable to provide a signal for resetting said hold latch flip flop to disable said hold switch means thereby removing the hold condition from said first line whereby unintentional release of said first line cannot occur.

Claim 4

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a pluraLity of four-wire lines connected to said termination circuits, seize means operatively associated with said first line termination circuit for seizing a first one of said lines including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit, hold means associated with said first line termination circuit including hold switch means operable when enabled to establish a D.C. supervision loop for said first line and a hold latch flip flop, said hold latch flip flop being set by said seize means to provide an enabling signal for said hold switch means in response to operation of said seize means to seize said first line, means in said multi-line telephone set for controlling said seize means to connect the transmit and receive paths of a second one of said lines to said local line circuit and to simultaneously disconnect the transmit and receive paths of said first line from said local line circuit without disabling the hold switch means for said first line whereby said first line is automatically placed in a hold condition, and release means operable to provide a signal for resetting said hold latch flip flop to disable said hold switch means thereby removing the hold condition from said first line whereby unintentional release of said first line cannot occur.

Claim 5

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits, seize means for seizing a first one of said lines including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit, control means in said multi-line set for controlling said seize means to connect the transmit and receive paths of a second one of said termination circuits to said local line circuit and to simultaneously place said first line in a hold condition, conference connect means including a plurality of conference relays operable when energized for individually connecting the transmit and receive paths of each of said lines to the transmit and receive paths of the other of said lines, and conference selection means including a plurality of logic gates controlled by said seize means and said control means for energizing a select one of said conference relays to connect the transmit and receive paths of said first and second lines in a local conference circuit connection.

Claim 6

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits, seize means for seizing a first one of said lines including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit, control means in said multi-line set for controlling said seize means to connect the transmit and receive paths of a second one of said termination circuits to said local line circuit and to simultaneously place said first line in a hold condition, conference connect means including a plurality of conference relays operable when energized for individually connecting the transmit and receive paths of each of said lines to the transmit and receive paths of the other of said lines, and conference selection means including a plurality of logic gates controlled by said seize means and said control means for energizing a select one of said conference relays to connect the transmit and receive paths of said first and second lines in a local conference circuit connection.

Claim 7

A multi-line telephone set as set forth in claim 3 which includes conference hold means operable to place said first and second lines on hold while the transmit and receive paths of said lines remain connected together in a local conference circuit.

Claim 8

A multi-line telephone set as set forth in claim 4 which further includes further seize means for seizing third and fourth ones of said four-wire lines and for controlling a further plurality of logic gates of said conference selection means to energize a select other one of said conference relays for connecting the transmit and receive paths of said third and fourth four-wire lines in a further local conference circuit connection independent of said connection between said first and said second lines.

Claim 9

A multi-line telephone set as set forth in claim 5 which further includes release means for releasing said conference connections simultaneously.

Claim 10

A multi-line telephone set as set forth in claim 5 which further includes means for breaking the conference connections between one of said pair of lines without affecting the conference connection between the other pair of lines.

Claim 11

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines coNnected to said line termination circuits, seize means for seizing a first one of said lines including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit, a coil and a transistor enabled by said seize means to provide a holding path for said coil to operate said connect means, means in said multi-line telephone set controlling said seize means to connect the transmit and receive paths of a second one of said termination circuits to said local line circuit and to simultaneously place said first line in a hold condition, conference selection means and conference connect means responsive to said conference selection means to connect the transmit and receive paths of said first and second lines in a local conference circuit connection and release means including a signal detecting circuit for causing said transistor to be disabled upon detection of a signal by said signal detecting circuit whereby the hold path for said coil is opened and said connect means is restored.

Claim 12

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines coNnected to said line termination circuits, seize means for seizing a first one of said lines including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit, a coil and a transistor enabled by said seize means to provide a holding path for said coil to operate said connect means, means in said multi-line telephone set controlling said seize means to connect the transmit and receive paths of a second one of said termination circuits to said local line circuit and to simultaneously place said first line in a hold condition, conference selection means and conference connect means responsive to said conference selection means to connect the transmit and receive paths of said first and second lines in a local conference circuit connection and release means including a signal detecting circuit for causing said transistor to be disabled upon detection of a signal by said signal detecting circuit whereby the hold path for said coil is opened and said connect means is restored.

Claim 13

A multi-line telephone set as set forth in claim 8 in which said seize means includes seize logic circuits that are set whenever said first line is seized, said release means being connected to said seize logic circuits for resetting said seize logic circuits upon detection of said signal by said signal detecting circuit whereby the conference circuit connection between said first and second lines is opened.

Claim 14

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits, a first one of said lines being connected to a switching center, and the line termination circuit for said first line including means for providing an indication of the on-hook or off-hook status of said first line, seize means for seizing said first line including connect means for connecting the transmit and receive path of said first line to the transmit and receive path of said local line circuit, means in said multi-line telephone set controlling said seize means to connect the transmit and receive paths of a second one of said line termination circuits to said local line circuit and simultaneously place said first line in a hold condition, conference selection means and conference connect means responsive to said conference selection means to connect the transmit and receive paths of said first and second lines in a local conference circuit connection, and means responsive to the receipt of a signal tone from said switching center via said first line for releasing the conference circuit in which said first line is connected whenever an on-hook status is indicated for said first line.

Claim 15

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits, a first one of said lines being connected to a switching center, and the line termination circuit for said first line including means for providing an indication of the on-hook or off-hook status of said first line, seize means for seizing said first line including connect means for connecting the transmit and receive path of said first line to the transmit and receive path of said local line circuit, means in said multi-line telephone set controlling said seize means to connect the transmit and receive paths of a second one of said line termination circuits to said local line circuit and simultaneously place said first line in a hold condition, conference selection means and conference connect means responsive to said conference selection means to connect the transmit and receive paths of said first and second lines in a local conference circuit connection, and means responsive to the receipt of a signal tone from said switching center via said first line for releasing the conference circuit in which said first line is connected whenever an on-hook status is indicated for said first line.

Claim 16

A multi-line telephone set as set forth in claim 3 wherein the line termination circuits for said first and second lines include separate summing amplifier means serially connected in the transmit paths of said first and second four-wire lines and in which said plurality of conference relays include a first conference relay for individually connecting the receive path of said first line to an input of the summing amplifier connected in the transmit path of said second four-wire line, and a second conference relay for individually connecting the receive path of said second line to an input of the summing amplifier connected in the transmit path of said first four-wire line.

Claim 17

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising a local line circuit having transmit and receive paths; a plurality of line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; detect means for detecting a signal indicative of the receipt of a call incoming over one of said linEs including means for distinguishing between an incoming priority call signal and an incoming non-priority call signal; indicator means for providing a first indication whenever a priority call is being received and a second indication whenever a non-priority call is being received; and seize means for seizing said line including means for connecting the transmit and receive paths of said one line to the transmit and receive paths of said local line circuit.

Claim 18

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising a local line circuit having transmit and receive paths; a plurality of line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; detect means for detecting a signal indicative of the receipt of a call incoming over one of said linEs including means for distinguishing between an incoming priority call signal and an incoming non-priority call signal; indicator means for providing a first indication whenever a priority call is being received and a second indication whenever a non-priority call is being received; and seize means for seizing said line including means for connecting the transmit and receive paths of said one line to the transmit and receive paths of said local line circuit.

Claim 19

A multi-line telephone set as set forth in claim 12 which includes hold means for providing an indication of the on-hook or off-hook status of said line and for causing said call signal to be inhibited when said line is seized.

Claim 20

A multi-line telephone set as set forth in claim 12 in which said indicator means includes an acoustic transducer and means for driving said transducer at a first rate whenever a priority call is being received and at a second rate whenever a non-priority call is being received.

Claim 21

A multi-line telephone set as set forth in claim 12 in which said indicator means includes a lamp and means for driving said lamp to flash at a first rate whenever a priority call is being received and at a second rate whenever a non-priority call is being received.

Claim 22

A multi-line telephone set as set forth in claim 15 in which said driving means includes a latch circuit connected to said detect means said latch circuit being latched whenever a call signal is detected by said detect means, and a gate circuit connected to said latch circuit for gating signals of a first frequency to said lamp whenever said latch circuit is latched and means for resetting said latch circuit after a predetermined time after said call signal ceases.

Claim 23

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising a local line circuit having transmit and receive paths; a plurality of line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; means for placing one of said lines in a hold condition; detect means for detecting the receipt of an incoming priority call over said one line; and indicator means for providing an indication that said incoming priority call is being received over said one line.

Claim 24

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising a local line circuit having transmit and receive paths; a plurality of line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; means for placing one of said lines in a hold condition; detect means for detecting the receipt of an incoming priority call over said one line; and indicator means for providing an indication that said incoming priority call is being received over said one line.

Claim 25

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising a local line circuit having transmit and receive paths; a plurality of line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; means for providing an indication that a non-priority call is being received over one of said lines; means for providing an audible indication that said non-priority call is being received by said set; and priority indicating means including means for providing a second visual indication and means for modifying said first audible indication whenever a priority call is received over one of said other lines while said non-priority call is being received over said one line.

Claim 26

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising a local line circuit having transmit and receive paths; a plurality of line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; means for providing an indication that a non-priority call is being received over one of said lines; means for providing an audible indication that said non-priority call is being received by said set; and priority indicating means including means for providing a second visual indication and means for modifying said first audible indication whenever a priority call is received over one of said other lines while said non-priority call is being received over said one line.

Claim 27

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising; a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; detect means for detecting the receipt of an incoming call over a first one of said lines; indicator means for providing an indication that said incoming call is being received over said first line; seize means for seizing said first line including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit; means in said multi-line set for controlling said seize means to connect the transMit and receive paths of a second one of said termination circuits to said local line circuit and to simultaneously place said first line in a hold condition; means for overriding said hold condition whereby said first line becomes connected to said local line circuit while said second line remains connected to said local line circuit; conference selection means and means responsive to said conference selection means to connect the transmit and receive paths of said first and second lines in a local conference circuit connection; conference hold means for placing said first and second lines on hold, whereby said first and second lines become disconnected from said local line circuit and remain connected in a local conference connection; and further seize means for seizing a third one of said lines including further connect means for connecting the transmit and receive paths of said third line to the transmit and receive paths of said local line circuit.

Claim 28

A four-wire multi-line telephone set for sending and receiving priority and non-priority calls; said telephone set comprising; a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit and receive paths for each of a plurality of four-wire lines connected to said termination circuits; detect means for detecting the receipt of an incoming call over a first one of said lines; indicator means for providing an indication that said incoming call is being received over said first line; seize means for seizing said first line including connect means for connecting the transmit and receive paths of said first line to the transmit and receive paths of said local line circuit; means in said multi-line set for controlling said seize means to connect the transMit and receive paths of a second one of said termination circuits to said local line circuit and to simultaneously place said first line in a hold condition; means for overriding said hold condition whereby said first line becomes connected to said local line circuit while said second line remains connected to said local line circuit; conference selection means and means responsive to said conference selection means to connect the transmit and receive paths of said first and second lines in a local conference circuit connection; conference hold means for placing said first and second lines on hold, whereby said first and second lines become disconnected from said local line circuit and remain connected in a local conference connection; and further seize means for seizing a third one of said lines including further connect means for connecting the transmit and receive paths of said third line to the transmit and receive paths of said local line circuit.

Claim 29

A multi-line set as claimed in claim 19 which includes means for releasing said first and second lines from said local conference connection independent of the connection of said third line.

Claim 30

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit paths for each of a plurality of four-wire lines connected to said termination circuits, means for seizing one of said lines including connect means for connecting the transmit and receive paths of said one four-wire line to the transmit and receive paths of said local line circuit, short circuit means for providing a short circuit across a portion of the transmit path of said local line circuit, control means for controlling said short circuit means removing said short circuit to permit transmission of speech over said local line circuit and said line, means for generating multi-frequency signals, and means responsive to said multi-frequency signals for inhibiting the operation of said control means during generation of said multi-frequency signals.

Claim 31

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of four-wire line termination circuits for providing separate transmit paths for each of a plurality of four-wire lines connected to said termination circuits, means for seizing one of said lines including connect means for connecting the transmit and receive paths of said one four-wire line to the transmit and receive paths of said local line circuit, short circuit means for providing a short circuit across a portion of the transmit path of said local line circuit, control means for controlling said short circuit means removing said short circuit to permit transmission of speech over said local line circuit and said line, means for generating multi-frequency signals, and means responsive to said multi-frequency signals for inhibiting the operation of said control means during generation of said multi-frequency signals.

Claim 32

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of line termination circuits each providing separate transmit and receive paths for a four-wire line connected thereto, and means for selectively connecting the transmit and receive paths of said termination circuits to the transmit and receive paths of said local line circuit, each line termination circuit including a socket having a plurality of terminals and a plug including a plurality of contact pins interconnected in sets by conductors, said contact pins being located in preselected positions on said plug whereby the interconnected contact pins interconnect a first predetermined set of terminals of said socket to provide a first mode of operation for said line termination circuit whenever said plug is removably inserted into said socket in a first position and the interconnected contact pins interconnect a second predetermined set of terminals of said socket to provide a second mode of operation for said line termination circuit whenever said plug is removably inserted into said socket in a second position.

Claim 33

A four-wire multi-line telephone set including a local line circuit having transmit and receive paths, a plurality of line termination circuits each providing separate transmit and receive paths for a four-wire line connected thereto, and means for selectively connecting the transmit and receive paths of said termination circuits to the transmit and receive paths of said local line circuit, each line termination circuit including a socket having a plurality of terminals and a plug including a plurality of contact pins interconnected in sets by conductors, said contact pins being located in preselected positions on said plug whereby the interconnected contact pins interconnect a first predetermined set of terminals of said socket to provide a first mode of operation for said line termination circuit whenever said plug is removably inserted into said socket in a first position and the interconnected contact pins interconnect a second predetermined set of terminals of said socket to provide a second mode of operation for said line termination circuit whenever said plug is removably inserted into said socket in a second position.

Claim 34

In a four-wire, multi-line telephone system including a plurality of four-wire telephone sets, each having a local line circuit and separate transmit and receive paths, a four-wire line termination circuit for connecting the four-wire transmit and receive paths of one of said telephone sets to a switching center, switching means associated with said one telephone set including connection means for selectively connecting the transmit and receive paths of said one telephone set to the transmit and receive paths of said four-wire line termination circuit, a multi-line network connected to said four-wire line termination circuit for establishing a party-line connection including said one four-wire telephone set and a pre-selected group of said plurality of four-wirE telephone sets, including means for introducing cross-talk between the transmit and receive paths of said four-wire telephone sets which are connected to said four-wire termination circuit, said multi-line network being connected to extend ringing signals received from said switching center by said four-wire line termination circuit to each of said telephone sets of said preselected group.

Claim 35

In a four-wire, multi-line telephone system including a plurality of four-wire telephone sets, each having a local line circuit and separate transmit and receive paths, a four-wire line termination circuit for connecting the four-wire transmit and receive paths of one of said telephone sets to a switching center, switching means associated with said one telephone set including connection means for selectively connecting the transmit and receive paths of said one telephone set to the transmit and receive paths of said four-wire line termination circuit, a multi-line network connected to said four-wire line termination circuit for establishing a party-line connection including said one four-wire telephone set and a pre-selected group of said plurality of four-wirE telephone sets, including means for introducing cross-talk between the transmit and receive paths of said four-wire telephone sets which are connected to said four-wire termination circuit, said multi-line network being connected to extend ringing signals received from said switching center by said four-wire line termination circuit to each of said telephone sets of said preselected group.

Claim 36

A system as set forth in claim 23 which includes means in said four-wire line termination circuit responsive to a signal from any one of the four-wire sets in said preselected group or said one four-wire telephone set to initiate a call to said associated switching center.

Claim 37

A system as set forth in claim 23 in which said four-wire line termination circuit includes jack means for receiving pre-programmed plugs, and which includes one pre-programmed plug for providing connections between said multi-line network and said four-wire line termination circuit to establish a party line circuit.

Claim 38

In a four-wire, multi-line telephone system including a plurality of four-wire telephone sets, each having a local line circuit and separate transmit and receive paths, a four-wire line termination circuit for connecting the four-wire transmit and receive paths of one of said telephone sets to a switching center, switching means associated with said one telephone set including connection means for selectively connecting the transmit and receive paths of said one telephone set to the transmit and receive paths of said four-wire line termination circuit, a multi-line network connected to said four-wire line termination circuit for establishing a party-line connection including said one four-wire telephone set and a pre-selected group of said plurality of four-wire telephone sets, said multi-line network and said line termination circuit being connected to extend signals indicating an off hook condition from the local line circuit of any one of said four wire telephone sets in said preselected group or said one multi-line set over the transmit path of each of the other of said four-wire multi-line telephone sets in said preselected group or said one multi-line set.

Claim 39

In a four-wire, multi-line telephone system including a plurality of four-wire telephone sets, each having a local line circuit and separate transmit and receive paths, a four-wire line termination circuit for connecting the four-wire transmit and receive paths of one of said telephone sets to a switching center, switching means associated with said one telephone set including connection means for selectively connecting the transmit and receive paths of said one telephone set to the transmit and receive paths of said four-wire line termination circuit, a multi-line network connected to said four-wire line termination circuit for establishing a party-line connection including said one four-wire telephone set and a pre-selected group of said plurality of four-wire telephone sets, said multi-line network and said line termination circuit being connected to extend signals indicating an off hook condition from the local line circuit of any one of said four wire telephone sets in said preselected group or said one multi-line set over the transmit path of each of the other of said four-wire multi-line telephone sets in said preselected group or said one multi-line set.