POWER BACKUP SYSTEM

摘要

An electrically powered node (3) of a telecommunications system has a battery power backup (37) associated with its power control unit (33). Under normal conditions it are maintained fully charged by means of trickle currents from the mains power feeds (14) to each of a number of mains- connected customer equipments (4), by way of the "final drop" (10) to the distribution point. These trickle currents are controlled by the respective power control units (33, 43), to prevent overcharging. Using an electrical copper connection (19) provided in parallel with the fibre connection (9), a battery backup (27) can also be maintained in nodes (2) further towards the exchange. These feeds are made reversible, so that if a power outage removes the power supply (14) from the customer premises (4), a "lifeline" plain telephone service between the exchange (1) and the telephone handset (5) is maintained over the connections (9, 10, 13), using the local battery backup (27, 37) in the remote nodes (2, 3). By limiting the service to simple telephony, the battery power (27, 37, 47) can be sufficient to maintain the service for a reasonable duration. The power management systems (23, 33, 43) can be used to transfer charge from one battery (27, 37) to another over the network according to the usage, or remaining life, of each battery (27, 37, 47).