Patent ID: 7545057

Claim:
Relay circuitry that operates in a closed-switch state when power is not supplied by power-sourcing equipment to the circuitry and in an open-switch state when power is supplied by the power-sourcing equipment to the circuitry, the relay circuitry comprising: a charge-pump circuit for causing the relay circuitry to be placed in the closed-switch state when power is not supplied by the power-sourcing equipment to the relay circuitry, wherein the charge-pump circuit is operative to store charge from input signals to the relay circuitry when the input signals are of a first polarity, and to use the stored charge to maintain the relay circuitry in the closed-switch state when the input signals are of a second substantially reverse polarity; and switching circuitry that is operative to switch the relay circuitry from the closed-switch state to the open-switch state when power is supplied by the power-sourcing equipment to the relay circuitry.