Telephone line sourced power supply
First Claim
1. A power supply for a device with circuitry requiring a supply voltage of a generally constant voltage, the device connectable to a telephone line, the circuitry including logic for indicating the device is requesting to be taken off-hook, comprising:
- means for providing the supply voltage to the circuitry, said supply voltage means including a power input;
a capacitor for providing power to said power input of said supply voltage means, a voltage being present across the capacitor;
means for providing voltage from the telephone line to said capacitor when the device is off-hook;
means for determining when the voltage across said capacitor falls below a first predetermined threshold; and
off-hook circuitry for forcing the device off-hook responsive to said means for determining when the voltage across said capacitor has fallen below said first predetermined threshold.
3 Assignments
0 Petitions
Accused Products
Abstract
In a telecommunication unit attached to a telephone line, power is provided by taking power from the telephone line when the unit is off-hook. When the unit remains on-hook, power is maintained to circuitry in the unit by a charge stored in a capacitor. When the capacitor'"'"'s charge is reduced to a level no longer able to sustain operation of the unit, the unit is briefly taken off-hook, allowing the capacitor to recharge. Charge control of the capacitor is performed either by discrete circuitry or by a microcontroller, and further includes logic provisions preventing the unit from remaining off-hook for an unduly long period of time.
79 Citations
13 Claims
-
1. A power supply for a device with circuitry requiring a supply voltage of a generally constant voltage, the device connectable to a telephone line, the circuitry including logic for indicating the device is requesting to be taken off-hook, comprising:
-
means for providing the supply voltage to the circuitry, said supply voltage means including a power input; a capacitor for providing power to said power input of said supply voltage means, a voltage being present across the capacitor; means for providing voltage from the telephone line to said capacitor when the device is off-hook; means for determining when the voltage across said capacitor falls below a first predetermined threshold; and off-hook circuitry for forcing the device off-hook responsive to said means for determining when the voltage across said capacitor has fallen below said first predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. An electrical device for communicating data over a telephone line and over a radio frequency channel, comprising:
-
circuitry for communicating data over the telephone line and the radio frequency channel, said circuitry requiring a supply voltage of a generally constant voltage, and said circuitry including logic for indicating the device is requesting to be taken off-hook; means for providing the supply voltage to said circuitry, said supply voltage means including a power input; a capacitor for providing power to said power input of said supply voltage means, a voltage being present across the capacitor; means for providing voltage from the telephone line to said capacitor when the device is off-hook; means for determining when the voltage across said capacitor falls below a first predetermined threshold; and off-hook circuitry for forcing the device off-hook responsive to said means for determining when the voltage across said capacitor has fallen below said first predetermined threshold.
-
Specification