Communication apparatus being selectively powered by a main power supply or a back-up power supply depending on the operating mode of the communication apparatus

Abstract

A main power supply supplies a supply target including a network connector with power for allowing the supply target to operate. The network connector operates by using power supplied from the main power supply. A network-event detector detects an electrical change in the telephone network as a network event. A backup power supply is provided separately from the main power supply and is charged with power supplied from the main power supply during operation of the main power supply. A normal-mode setter operates by using power supplied from the backup power supply in a stopped mode, and to set an operational mode to a normal mode in response to occurrence of a voltage reduction state in a backup voltage. A forcing discharger discharges charged power of the backup power supply in response to the network-event detector detecting the network event in the stopped mode, thereby generating the voltage reduction state.