Patent ID: 6320494
Filing Date: 2001-11-20
Classification: H04B

Abstract:
A system for full duplex communication between a local station and a remote station with remote station power provided by the local station, and with communication and power transmission all occurring on first and second conductors, said system comprising in the local station,a) a modulating voltage power supply having a first power terminal for connection to the first conductor, a second power terminal, and a voltage control terminal for receiving a local data signal, and providing a first preselected power voltage between the first and second power terminals responsive to a first value of the local data signal, and a second preselected power voltage lower than the first power voltage between the first and second power terminals responsive to a second value of the local data signal;b) a current sensor having a first current sensor terminal connected to the first power terminal, a second current sensor terminal in electrical connection to the first current sensor terminal and supplying current received at the first current sensor terminal, said second sensor terminal for connection to the first conductor, and said current sensor having a current signal terminal providing a current sensor signal having a first value responsive to current greater than a preselected value flowing from the first to the second current sensor terminal, and a second value otherwise;and in the remote station,c) a voltage sensor having i) first and second voltage sensor terminals for connection through the first and second conductors respectively to the second current sensor terminal and to the second power terminal in the local station, and ii) a voltage signal terminal providing a voltage sensor signal having a first value when the voltage between the first and second voltage sensor terminals corresponds to the first preselected power voltage, and a second value when the voltage between the first and second voltage sensor terminals corresponds to the second preselected power voltage; andd) a current shunt connected between the first and second voltage sensor terminals and having a current control terminal for receiving a remote data signal, said shunt having a non-zero first impedance responsive to a first value of the remote data signal, and a second impedance greater than the first impedance responsive to a second value of the remote data signal,wherein the current sensor signal reproduces the data content of the remote data signal and the voltage sensor signal reproduces the data content of the local data signal.