Telephone line loop extender

Claim 2

A telephone line loop extender comprising: first and second bidirectional current flow control paths, said first and second bidirectional current flow control paths being arranged for connection in series with respective first and second lines of a telephone line loop, each of said first and second bidirectional current flow control paths include a pair of cross coupled transistors forming one of the current flow control paths thereof, said cross coupled transistors having the collectoremitter current path thereof connected to the base of the other of said transistors for biasing the same to a conductive condition upon increased current flow of said one of said transistors, polarity sensing means associated with each of said bidirectional current flow control paths for sensing a voltage polarity at a central office and thereby causing a current flow in one direction through said first bidirectional current flow control path and in the opposite direction in said second bidirectional current flow control path, a single polarity voltage source associated with each of said first and second bidirectional current flow control paths, only one of said voltage sources at a given time being inserted into the telephone line loop by proper directional switching of said first and second bidirectional current flow control paths, and a high impedance current coupling between said first and second bidirectional current flow control paths for rendering operative a current flow path means in one of the said first and second bidirectional current flow control paths and for switchably inserting said single polarity voltage source in the other of said first and second bidirectional current flow control paths, whereby current is added to the telephone line loop by being inserted into one of the pair of telephone lines.

Claim 3

The telephone line loop extender according to claim 1, wherein reference voltage means is connected to the base emitter junction of each of said pair of transistors.

Claim 4

The telephone line loop extender according to claim 1, wherein said high impedance current coupling is formed of a resistor.

Claim 5

A telephone line loop extender comprising: first and second bidirectional current flow control paths, said first and second bidirectional current flow control paths being arranged for connection in series with respective first and second lines of a telephone line loop, polarity sensing means associated with each of saId bidirectional current flow control paths for sensing a voltage polarity at a central office and thereby causing a current flow in one direction through said first bidirectional current flow control path and in the opposite direction in said second bidirectional current flow control path, a single polarity voltage source associated with each of said first and second bidirectional current flow control paths, only one of said voltage sources at a given time being inserted into the telephone line loop by proper directional switching of said first and second bidirectional current flow control paths, a high impedance current coupling between said first and second bidirectional current flow control paths for rendering operative a current flow path means in one of the said first and second bidirectional current flow control paths and for switchably inserting said single polarity voltage source in the other of said first and second bidirectional current flow control paths, whereby current is added to the telephone line loop by being inserted into one of the pair of telephone lines, and including a bypass network shunting each of said first and second bidirectional current flow control paths, said bypass circuit being formed of parallel connected capacitor, diode and resistor components.

Claim 6

A telephone line loop extender comprising: first and second bidirectional current flow control paths, said first and second bidirectional current flow control paths being arranged for connection in series with respective first and second lines of a telephone line loop, polarity sensing means associated with each of saId bidirectional current flow control paths for sensing a voltage polarity at a central office and thereby causing a current flow in one direction through said first bidirectional current flow control path and in the opposite direction in said second bidirectional current flow control path, a single polarity voltage source associated with each of said first and second bidirectional current flow control paths, only one of said voltage sources at a given time being inserted into the telephone line loop by proper directional switching of said first and second bidirectional current flow control paths, a high impedance current coupling between said first and second bidirectional current flow control paths for rendering operative a current flow path means in one of the said first and second bidirectional current flow control paths and for switchably inserting said single polarity voltage source in the other of said first and second bidirectional current flow control paths, whereby current is added to the telephone line loop by being inserted into one of the pair of telephone lines, and including a bypass network shunting each of said first and second bidirectional current flow control paths, said bypass circuit being formed of parallel connected capacitor, diode and resistor components.

Claim 7

A telephone line loop extender comprising: first and second bidirectional current flow control paths, said first and second bidirectional current flow control paths being arranged for connection in series with respective first and second lines of a telephone line loop, said first and second bidirectional current flow control paths each include a pair of cross coupled transistors forming one of the current flow control paths thereof, one of said transistors having the emitter-collector current path thereof connected to the base of the other transistor for biasing the same to a conductive condition, a semiconductor switching device connected in series with said single polarity voltage source and forming the other current flow control path in opposite conductive polarity of said pair of transistors, said semiconductor switch inserting the said voltage source into the circuit when said pair of transistors are maintained in a non-conductive state, polarity sensing means associated with each of said bidirectional current flow control paths for sensing a voltage polarity at a central office and thereby causing a current flow in one direction through said first bidirectional current flow control path and in the opposite direction in said second bidirectional current flow control path, a single polarity voltage source associated with each of said first and second bidirectional current flow control paths, only one of said voltage sources at a given time being inserted into the telephone line loop by proper directional switching of said first and second bidirectional current flow control paths, and a high impedance current coupling between said first and second bidirectional current flow control paths for rendering operative a current flow path means in one of the said first and second bidirectional current flow control paths and for switchably inserting said single polarity voltage source in the other of said first and second bidirectional current flow control paths, whereby current is added to the telephone line loop by being inserted into one of the pair of telephone lines.

Claim 8

A telephone line loop extender comprising: first and second bidirectional current flow control paths, said first and second bidirectional current flow control paths being arranged for connection in series with respective first and second lines of a telephone line loop, said first and second bidirectional current flow control paths each include a pair of cross coupled transistors forming one of the current flow control paths thereof, one of said transistors having the emitter-collector current path thereof connected to the base of the other transistor for biasing the same to a conductive condition, a semiconductor switching device connected in series with said single polarity voltage source and forming the other current flow control path in opposite conductive polarity of said pair of transistors, said semiconductor switch inserting the said voltage source into the circuit when said pair of transistors are maintained in a non-conductive state, polarity sensing means associated with each of said bidirectional current flow control paths for sensing a voltage polarity at a central office and thereby causing a current flow in one direction through said first bidirectional current flow control path and in the opposite direction in said second bidirectional current flow control path, a single polarity voltage source associated with each of said first and second bidirectional current flow control paths, only one of said voltage sources at a given time being inserted into the telephone line loop by proper directional switching of said first and second bidirectional current flow control paths, and a high impedance current coupling between said first and second bidirectional current flow control paths for rendering operative a current flow path means in one of the said first and second bidirectional current flow control paths and for switchably inserting said single polarity voltage source in the other of said first and second bidirectional current flow control paths, whereby current is added to the telephone line loop by being inserted into one of the pair of telephone lines.