Party-line bridge-lifter

Claim 2

In a communication system, a transmission line, a pair of station lines, means for maintaining an impedance match between said transmission line and enabled ones of said station lines bridged to said transmission line comprising inductance means, impedance matching means, first means responsive to an enabled state of either of said bridged station lines for selectively connecting said inductance means in series with the other said station line, and second means responsive to the enabled state of said one station line in bridged combination with the enabled state of the other said station line for connecting said impedance matching means between said transmission line and both said bridged station lines.

Claim 3

In a communication system, a transmission line, a pair of station lines, means for maintaining an impedance match between said transmission line and enabled ones of said station lines bridged to said transmission line comprising inductance means, impedance matching means, first means responsive to an enabled state of either of said bridged station lines for selectively connecting said inductance means in series with the other said station line, and second means responsive to the enabled state of said one station line in bridged combination with the enabled state of the other said station line for connecting said impedance matching means between said transmission line and both said bridged station lines.

Claim 4

In a communication system, a transmission line, a pair of station lines, means for maintaining an impedance match between said transmission line and enabled ones of said station lines bridged to said transmission line comprising inductance means, impedance matching means, first means responsive to an enabled state of either of said bridged station lines for selectively connecting said inductance means in series with the other said station line, and second means responsive to the enabled state of said one station line in bridged combination with the enabled state of the other said station line for connecting said impedance matching means between said transmission line and both said bridged station lines.

Claim 5

In a communication system, the combination set forth in claim 1 further comprising line relay means individual to each said station line and serially inserted in each said station line for detecting the enabled state of said station line.

Claim 6

In a communication system, the combination set forth in claim 2 in which said second means further comprises means controlled by said line relay means of said one station line in combination with said line relay means of said other station line for indicating the said enabled state of all said lines.

Claim 7

In a communication system, the combination set forth in claim 2 in which said first means and said second means comprise slave relay means individual to each said station line and controlled by said line relay means.

Claim 8

In a communication system, the combination set forth in claim 4 in which said first means further comprises means controlled by the said slave relay means individual to each said other station line for directly connecting said one station line to said transmission line.

Claim 9

In a communication system, the combination set forth in claim 1 in which said impedance matching means comprises means for equaling the reflected combined impedances of said bridged station lines and the impedance of said transmission line including transformer means having a secondary winding connected across said bridged station lines and a primary winding connected across said transmission line.

Claim 10

In a communication system, the combination set forth in claim 6 in which said impedance matching means further comprises capacitive means connected in parallel with said windings of said transformer means.

Claim 11

In an impedance matching system, a first port terminating apparatus having a predetermined level of impedance, a pair of second ports, each connectable to said first port and operable to alternatively indicate a first and second state, said first state corresponding to said predetermined level of impedance, and electromechanical switching means for maintaining an impedance match between said first port and said second ports by selectively connecting said second ports to said first port comprising inductance means, transformer means, means responsive to the first state of any one of said second ports concurrently with the second state of the other second port for serially inserting said inductance means between the other said second port and said first port, and means responsive to the first state of one of said second ports in bridged combination with the first state of the other said second port for serially inserting said transformer means between said first port and bridged ones of said second ports.

Claim 12

In an impedance matching system, a first port terminating apparatus having a predetermined level of impedance, a pair of second ports, each connectable to said first port and operable to alternatively indicate a first and second state, said first state corresponding to said predetermined level of impedance, and electromechanical switching means for maintaining an impedance match between said first port and said second ports by selectively connecting said second ports to said first port comprising inductance means, transformer means, means responsive to the first state of any one of said second ports concurrently with the second state of the other second port for serially inserting said inductance means between the other said second port and said first port, and means responsive to the first state of one of said second ports in bridged combination with the first state of the other said second port for serially inserting said transformer means between said first port and bridged ones of said second ports.

Claim 13

In a party-line telephone system, a switching network linkage path connected to a source of direct current, a plurality of telephone stations each comprising means for transmitting and receiving speech signals only when in an off-hook state and means for completing a direct current path when in Said off-hook state, inductance means, transformer means, means associated with each of said stations for the transmission of said speech signals between a said off-hook station and said linkage path, means connected in series with each of said transmission means for detecting the flow of direct current in said transmission means, means controlled by said detecting means for connecting said transmission means to said linkage path, means operable in response to enabling of one of said detecting means of one of said stations in said off-hook state for matching impedance of said linkage path with impedance of said transmission means associated with said off-hook station by selectively connecting said inductance means in between said linkage path and said transmission means associated with each other said station, and means enabled by said enabling of said one detecting means in combination with said enabling of said other detecting means for maintaining said impedance match by connecting said transformer means between said linkage path and bridged ones of said transmission means associated with said off-hook stations.

Claim 14

In a party-line telephone system, a switching network linkage path connected to a source of direct current, a plurality of telephone stations each comprising means for transmitting and receiving speech signals only when in an off-hook state and means for completing a direct current path when in Said off-hook state, inductance means, transformer means, means associated with each of said stations for the transmission of said speech signals between a said off-hook station and said linkage path, means connected in series with each of said transmission means for detecting the flow of direct current in said transmission means, means controlled by said detecting means for connecting said transmission means to said linkage path, means operable in response to enabling of one of said detecting means of one of said stations in said off-hook state for matching impedance of said linkage path with impedance of said transmission means associated with said off-hook station by selectively connecting said inductance means in between said linkage path and said transmission means associated with each other said station, and means enabled by said enabling of said one detecting means in combination with said enabling of said other detecting means for maintaining said impedance match by connecting said transformer means between said linkage path and bridged ones of said transmission means associated with said off-hook stations.

Claim 15

In a party-line telephone system, a telephone switching network linkage path connected to a source of direct current, at least two telephone station subsets each comprising means for transmitting and receiving speech signals only when in an off-hook state and means for completing a direct current path when in said off-hook state, a plurality of conductor pairs wherein each said conductor pair is connected to one of said subsets for the transmission of said speech signals between said off-hook station and said linkage path, a plurality of inductors, a transformer, a plurality of line relays wherein each said line relay is connected in series with one of said conductor pairs for detecting the flow of direct current in said conductor pair, a plurality of other relays each individual to one of said line relays and controlled by said line relay, each said other relay comprising a plurality of break contacts corresponding to a released state and each said other relay further comprising a plurality of make contacts corresponding to an operated state, means comprising said break contacts for connecting said conductor pairs to said linkage path, means comprising said make contacts of any one of said other relays enabled by an enabled one of said line relays for matching impedance of said linkage path with impedance of one of said conductor pairs connected to an off-hook one of said subsets by selectively connecting said inductors in between said linkage path and each of the other said line relays, and means comprising the said make contacts of said enabled one other relay in combination with the said make contacts of enabled said other relays for maintaining said impedance match with bridged ones of said conductor pairs connected to said off-hook subsets by connecting said transformer between said linkage path and all said line relays connected in series with said bridged conductor pairs.

Claim 16

In a party-line telephone system, a telephone switching network linkage path connected to a source of direct current, at least two telephone station subsets each comprising means for transmitting and receiving speech signals only when in an off-hook state and means for completing a direct current path when in said off-hook state, a plurality of conductor pairs wherein each said conductor pair is connected to one of said subsets for the transmission of said speech signals between said off-hook station and said linkage path, a plurality of inductors, a transformer, a plurality of line relays wherein each said line relay is connected in series with one of said conductor pairs for detecting the flow of direct current in said conductor pair, a plurality of other relays each individual to one of said line relays and controlled by said line relay, each said other relay comprising a plurality of break contacts corresponding to a released state and each said other relay further comprising a plurality of make contacts corresponding to an operated state, means comprising said break contacts for connecting said conductor pairs to said linkage path, means comprising said make contacts of any one of said other relays enabled by an enabled one of said line relays for matching impedance of said linkage path with impedance of one of said conductor pairs connected to an off-hook one of said subsets by selectively connecting said inductors in between said linkage path and each of the other said line relays, and means comprising the said make contacts of said enabled one other relay in combination with the said make contacts of enabled said other relays for maintaining said impedance match with bridged ones of said conductor pairs connected to said off-hook subsets by connecting said transformer between said linkage path and all said line relays connected in series with said bridged conductor pairs.