Cellular car telephone dialing controller

Central office filter system and method

Circuit and method for automatic memory dialing

Circuit and method for automatically cutting off a speech path a

Circuit and method for detecting telephone line status and telep

Circuit arrangement for a telephone station with earth connectio

Circuit arrangement for a telephone station with ground connecti

Circuit arrangement for echo suppression

Circuit arrangement for generating an acoustic ringing signal in

Circuit arrangement for the connection of line circuits of a dig

Circuit device for controlling the actuated state of an electric

Circuit for detecting current variations

Circuit for detection of off-hook condition of extension telepho

Circuit for evaluating call signals in a telecommunication syste

Circuit for reducing voltage peak in interfacing with a...

Circuit for sensing telephone line conditions

Circuit for surge voltage protection in electronic telephone sta

Circuit for transmitting voice signals and dial pulses

Circuit to detect the hook status and ringing at the CPE end of

Circuitry for recognizing two-tone compound signals in telephone