Apparatus for controlling the application of telephone line power in a telephone set

DETAILED DESCRIPTION The problems and limitations discussed above are overcome by the present apparatus for controlling the application of telephone line power in a telephone set.
A telephone set in accordance with the present invention includes a power supply capable of being charged when the telephone set is in either an on or off-hook switchhook condition.
First and second regulators regulate the charging of first and second voltage storage means of the power supply.
One storage means provides power for a prolonged period of time to a random access memory associated with a data processor as, for example, when the telephone set is unplugged from the telephone line and moved to another jack at the telephone customer's premises.
The power supply derives an on-hook charging input through a resistance from the telephone central office side of a dial pulsing and switchhook circuit.
An off-hook charging input is derived from the telephone station circuitry side of the dial pulsing and switchhook circuit.
A telephone set in accordance with the present invention further includes a voltage threshold detector circuit for controlling the application of power by monitoring the power supply voltage and actuating a power-down of power consumptive elements.
When the voltage provided by the power supply falls below a threshold value, the voltage threshold detector circuit, for example, actuates a power-down of the data processor.
Another means for controlling the application of power supply voltage and, hence, the telephone line voltage is a telephone impedance switch.
When the data processor recognizes that an element such as a loudspeaker amplifier requiring a high voltage for operation is to be activated, the telephone impedance switch intentionally increases the direct current resistance of the telephone set.
This action increases the line voltage across the telephone set's terminals.
The increased voltage then is transmitted through the off-hook charging input and through the power supply to that element, in this case the loudspeaker amplifier, which requires it