Telecommunications system, a subscriber unit, and a television s
Telephone apparatus
Telephone device for preventing a long-term on-line state result
Telephone headset on-line indicator
Telephone interface circuit
Telephone line bridging sensor
Telephone line coupler
Telephone line coupler
Telephone line coupler
Telephone line interface circuit
Telephone line loop current regulator
Telephone loop current modulator
Telephone ring signal detector
Telephone set with on-hook line seizure
Telephone subscriber circuit with galvanic isolation
Telephone subscriber line voltage change detection
Telephone subscribers' circuits
Telephone system
Telephone terminal apparatus and method
Telephone terminal device with means for detecting abandonment o