Patent ID: 7103178

Claim:
An apparatus for controllably supplying power to a line circuit that couples telecommunication signals to a telephone line comprising: a tip amplifier and a ring amplifier, coupled to said telephone line, each of said tip amplifier and said ring amplifier including signal amplification circuitry that is operative to amplify telecommunication signals for application to said telephone line, and wherein only one of said tip amplifier and said ring amplifier contains loop current supply circuitry which is controllably operative to couple a source of loop current to said telephone line, while the other of said tip amplifier and said ring amplifier contains no loop current supply circuitry; and a control circuit, which, for an on-hook condition of a telecommunication circuit device coupled to said telephone line, is operative to disable said other of said tip amplifier and said ring amplifier, and to disable signal amplification circuitry of said only one of said tip amplifier and said ring amplifier, and to enable said loop current supply circuitry of said only one of said tip amplifier and said ring amplifier and thereby cause said loop current supply circuitry to couple said source of loop current to said telephone line, so that, in response to said telecommunication circuit device transitioning from said on-hook condition to an off-hook condition, loop current may flow from said loop current supply circuitry through said telephone line, and wherein said control circuit is further operative to enable operation of signal amplification circuitry of each of said tip amplifier and said ring amplifier, in response to said telecommunication circuit device transitioning from said on-hook condition to an off-hook condition.