Method and apparatus for implementing a bandlimited ringing...

Method and apparatus for initiating telephone calls using a...

Method and apparatus for installing telephone intercom-voice...

Method and apparatus for non-disruptive telecommunication...

Method and apparatus for non-disruptive telecommunication...

Method and apparatus for off-hook detection

Method and apparatus for performing high-density DTMF,...

Method and apparatus for performing spectral processing in...

Method and apparatus for periodic signal detection

Method and apparatus for processing an incoming telephone call s

Method and apparatus for producing ringing tones in a...

Method and apparatus for programming guestroom telephones

Method and apparatus for providing customized ringbacks

Method and apparatus for pulse/tone detection and selection

Method and apparatus for registering multiple phone numbers...

Method and apparatus for remote doorbell answering

Method and apparatus for returning a false special...

Method and apparatus for ring again feature for a telephone...

Method and apparatus for routing a dialed telephone number

Method and apparatus for searching a database