Phone control center for a life safety network

Polarity ring director

Polarity ring director

Private branch exchange apparatus

Process for assigning a called number to customer premises...

Programmable selective ringing circuit and method for party tele

Reserved speech path forming method in a parallel-connected tele

Secure anti-jamming wireless party line

Selective ringing circuit for a telephone

Solid state remote actuable switch

Station controller for distributed single line PABX

Switching apparatus for use in telephone house wiring

Telecommunication controller having a telephone line sharing fun

Telecommunications device with means for learning and responding

Telecommunications subscriber line interface circuit and party i

Telephone answering system and apparatus for direct caller selec

Telephone answering system and apparatus for direct caller selec

Telephone line device

Telephone off-hook detector circuit

Telephone port with automatic detection and secure