BACKUP BATTERY POWER SUPPLY FOR MICROPROCESSOR BASED TELEPHONE

摘要

BACKUP BATTERY POWER SUPPLY FOR MICROPROCESSOR BASED TELEPHONE A circuit arrangement for use in telephone instruments which require battery backup for memory retention and microprocessor operation during such procedures as pulse dial address signalling where no power can be supplied by the telephone subscriber's line. Bipolar solid state circuitry may be used to provide the necessary backup power supply during these periods.