Backup battery power supply for microprocessor based telephones
Backup power supply at subscriber terminal
Battery boosted dial memory
Battery feed circuit
Battery feed circuit
Battery feed circuit for a pair of subscriber lines
Battery feed circuit for a telephone system
Battery feed circuit for supplying feed current to telephone set
Battery feed for telephone line cards
Battery switching in a telephone subscriber line interface circu
Battery-feed circuit for exchange
Bidirectional adaptive voice frequency repeater
Bipolar pulse forming line