Polarity reversal circuit

Claim 2

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing polarity across said third and fourth terminals comprising a first voltage source, a second voltage source, means for generating first and second momentary control signals, first, second, third and fourth coupling devices each having first, second and control electrodes, means for interconnecting said first, second, third And fourth coupling devices to form a bistable circuit connected between said first and second and third and fourth terminals, said first and third coupling device first electrodes being connected to said first voltage source, said second and fourth coupling device first electrodes being connected to said second voltage source, means for connecting said first and second coupling device second electrodes to said third terminal, means for connecting said second and fourth coupling device second electrodes to said fourth terminal, the control electrodes of said coupling devices being connected to said interconnecting means, said interconnecting means being responsive to said first control signal for rendering said first and fourth coupling devices conductive to couple the first voltage from said first voltage source to said third terminal via said first coupling device and to couple the second voltage from said second voltage source to said fourth terminal via said fourth coupling device, and said interconnecting means being responsive to said second control signal for rendering said second and third coupling devices conductive to couple said second voltage from said second voltage source to said third terminal via said second coupling device and to couple said first voltage from said first voltage source to said fourth terminal via said third coupling device.

Claim 3

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing polarity across third and fourth terminals according to claim 1 wherein said interconnecting means comprises a first switching device connected between said first terminal and said first coupling device control electrode and having first and second control electrodes, a second switching device connected between said second terminal and said second coupling device control electrode and having a control electrode, a third switching device connected between said first terminal and said third coupling device control electrode and having first and second control electrodes, a fourth switching device connected between said second terminal and said fourth coupling device control electrode and having a control electrode, means for coupling said first and second coupling device second electrodes to the first control electrode of said third switching device and the control electrode of said fourth switching device, means for coupling said third and fourth coupling device second electrodes to the first control electrode of said first switching device and the control electrode of said second switching device, means for applying said first control signal to the second control electrode of said third switching device, and means for applying said second control signal to the second control electrode of said first switching device.

Claim 4

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing polarity across said third and fourth terminals according to claim 2 wherein each of said first, second, third and fourth coupling devices comprises a transistor having collector, emitter and base electrodes, said transistor collector corresponding to said coupling device first electrode, said transistor emitter corresponding to said coupling device second electrode and said transistor base corresponding to said coupling device control electrode.

Claim 5

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing polarity across said third and fourth terminals according to claim 3 wherein each of said first, second, third and fourth switching devices comprises an insulated gate field effect transistor (IGFET) having source, drain and gate electrodes, said first and third IGFET drains being connected to said first terminal, said second and fourth IGFET drains being connected to said second terminal, said first IGFET sourCe being connected to said first transistor base, said second IGFET source being connected to said second transistor base, said third IGFET source being connected to said third transistor base, said fourth IGFET source being connected to said fourth transistor base, said first and third switching device first control electrodes corresponding to said first and third IGFET first gates and said second and fourth switching device control electrodes corresponding to said second and fourth IGFET gates.

Claim 6

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing polarity across said third and fourth terminals according to claim 4 wherein said first voltage source comprises a positive voltage source and said second voltage source comprises a negative voltage source.

Claim 7

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing polarity across said third and fourth terminals according to claim 4 wherein said first voltage source comprises a ground reference source and said second voltage source comprises a negative battery.

Claim 8

A polarity reversal signaling circuit comprising first and second terminals connected to an electronic trunk circuit and third and fourth terminals connected to a trunk, a positive voltage source, a negative voltage source, means for generating first and second momentary control signals, and a bistable switching circuit connected between said first and second terminals and said third and fourth terminals operative in a first state responsive to said first control signal to apply a positive voltage to said third terminal and a negative voltage to said fourth terminal and operative in a second state responsive to said second control signal to apply a negative voltage to said third terminal and a positive voltage to said fourth terminal and operative in both states to transfer information from said first and second terminals to said third and fourth terminals, said bistable circuit comprising first, second, third and fourth transistors, each having a collector, an emitter and a base, said first and third transistor collectors being connected to said positive voltage source, said second and fourth transistor collectors being connected to said negative voltage source, said first and second transistor emitters being connected to said third terminal, said second and fourth transistor emitters being connected to said fourth terminal, first, second, third and fourth IGFET switches each having source, drain and gate electrodes, said first and third IGFET switch drains being connected to said first terminal, said first IGFET source being connected to said first transistor base, said third IGFET source being connected to said third transistor base, said second and fourth IGFET drains being connected to said second terminal, said second IGFET source being connected to said second transistor base, said fourth IGFET source being connected to said fourth transistor base, means for connecting said first and second transistor emitters to one gate of said third IGFET switch and to the gate of said fourth IGFET switch, means for connecting said third and fourth transistor emitters to one gate of said first IGFET switch and to the gate of said second IGFET switch, means for applying said first control signal to the other gate of said third IGFET switch to put said bistable circuit in its first state, and means for applying said second control signal to the other gate of said first IGFET switch to put said bistable circuit in its second state.

Claim 9

A polarity reversal signaling circuit comprising first and second terminals connected to an electronic trunk circuit and third and fourth terminals connected to a trunk, a positive voltage source, a negative voltage source, means for generating first and second momentary control signals, and a bistable switching circuit connected between said first and second terminals and said third and fourth terminals operative in a first state responsive to said first control signal to apply a positive voltage to said third terminal and a negative voltage to said fourth terminal and operative in a second state responsive to said second control signal to apply a negative voltage to said third terminal and a positive voltage to said fourth terminal and operative in both states to transfer information from said first and second terminals to said third and fourth terminals, said bistable circuit comprising first, second, third and fourth transistors, each having a collector, an emitter and a base, said first and third transistor collectors being connected to said positive voltage source, said second and fourth transistor collectors being connected to said negative voltage source, said first and second transistor emitters being connected to said third terminal, said second and fourth transistor emitters being connected to said fourth terminal, first, second, third and fourth IGFET switches each having source, drain and gate electrodes, said first and third IGFET switch drains being connected to said first terminal, said first IGFET source being connected to said first transistor base, said third IGFET source being connected to said third transistor base, said second and fourth IGFET drains being connected to said second terminal, said second IGFET source being connected to said second transistor base, said fourth IGFET source being connected to said fourth transistor base, means for connecting said first and second transistor emitters to one gate of said third IGFET switch and to the gate of said fourth IGFET switch, means for connecting said third and fourth transistor emitters to one gate of said first IGFET switch and to the gate of said second IGFET switch, means for applying said first control signal to the other gate of said third IGFET switch to put said bistable circuit in its first state, and means for applying said second control signal to the other gate of said first IGFET switch to put said bistable circuit in its second state.

Claim 10

A polarity reversal signaling circuit according to claim 7 wherein said first and third transistors comprise NPN transistors, said third and fourth transistors comprise PNP transistors, said first and third IGFET switches comprise p-type IGFETs and said third and fourth IGFET switches comprise n-type IGFETs.

Claim 11

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing voltage polarity across said third and fourth terminals, comprising a first voltage source, a second voltage source, means for generating first and second control signals, and a bistable circuit connected between said first and second terminals and said third and fourth terminals, said bistable circuit comprising first, second, third and fourth coupling devices and a switching network interconnecting said first, second, third and fourth coupling devices, said bistable circuit being responsive to said first control signal for coupling said first voltage to said third terminal via said first coupling device and for coupling said second voltage to said fourth terminal via said fourth coupling device, said bistable circuit being responsive to said second control signal for coupling said first voltage to said fourth terminal via said third coupling device and for coupling said second voltage to said third terminal via said second coupling device.

Claim 12

A polarity reversal circuit for transferring signals between first and second terminals and third and fourth terminals and for selectively reversing voltage polarity across said third and fourth terminals, comprising a first voltage source, a second voltage source, means for generating first and second control signals, and a bistable circuit connected between said first and second terminals and said third and fourth terminals, said bistable circuit comprising first, second, third and fourth coupling devices and a switching network interconnecting said first, second, third and fourth coupling devices, said bistable circuit being responsive to said first control signal for coupling said first voltage to said third terminal via said first coupling device and for coupling said second voltage to said fourth terminal via said fourth coupling device, said bistable circuit being responsive to said second control signal for coupling said first voltage to said fourth terminal via said third coupling device and for coupling said second voltage to said third terminal via said second coupling device.