1
Sanford J Morganstein, Bakulesh A Mehta, Herbert B Krakau, Neil F N Milsted, Mark D Klecka: Busy/no-answer call completion equipment. Dytel Corporation, Jerry W Mills, Roger N Chauza, February 28, 1989: US04809321 (214 worldwide citation)

Call completion equipment (10) is disclosed for use with a switching system (14) for assisting callers to complete telephone calls thereto. If a primary destination telephone set (16) is busy or does not answer, a message is transmitted from a message storage unit (54) to the calling party. The mess ...


2
Sanford J Morganstein, Bakulesh A Mehta, Herbert B Krakau, Neil F N Milsted, Mark D Klecka: Busy/no-answer call completion equipment. Dytel Corporation, Baker Mills & Glast, June 19, 1990: US04935958 (53 worldwide citation)

Apparatus for recognizing a telephone call supervision signal by comparing its frequency and cadence to the frequency and cadence of a previously learned call supervision signal is provided as part of call completion equipment (10). Call progress tone detector (50) receives a call supervision signal ...