Adaptive no balance DX signalling circuit

Apparatus and method for a highly efficient low power driver...

Apparatus and method for determining the state of a telephone li

Apparatus and method for providing a telephone user with control

Apparatus and method to detect telephony signaling states

Apparatus for automatically recovering speech path of telephone

Apparatus for remotely determining hook status conditions

Apparatus for telephone extension control

Apparatus for transmitting and/or receiving balanced signals on

Arrangement for determining switch port status at an adjunct pro

Audible signaling device for informing when a telephone line is

Auxiliary attenuator arrangement for use in voice-switched speak

Call signal detecting device

Caller identification interface using line reversal detection

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 the connection of line circuits of a dig