Edward William Underhill

US Patent:

44131593, Nov 1, 1983

Filed:

Apr 2, 1982

Appl. No.:

6/364752

Inventors:

Donald D. Huizinga - Indianapolis IN
Donald R. Means - Indianapolis IN
Edward W. Underhill - Knightstown IN

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04M 131

US Classification:

179 90K

Abstract:

In order to provide push-button telephone service to those telephone systems not equipped to respond to multifrequency dialing signals, it is necessary to convert push-button dialed digits into conventional dial pulses. A pulse train consisting of make and break intervals representing the dialed digit is electronically converted (107) into a corresponding series of make and break intervals on the telephone line (102, 103) by switching (106, 108-1, 108-2) a pulsing transistor (101) that is in series with the telephone line ON and OFF. In order to keep the pulsing transistor ON during nondialing intervals and during each make interval, and not attenuate the voice signal, the pulsing transistor is biased by an adjustable current source (105). The current needed to bias the pulsing transistor ON is linearly related to the telephone line current flowing through the emitter-collector path of the transistor, and which varies considerably from station-to-station. In order to minimize the current needed to bias the pulsing transistor, a current sensor (104) derives a signal proportional to the line current which, in turn, is fed back to the current source (105 ) in order to adjust the bias current to be proportional to the line current.

US Patent:

40469727, Sep 6, 1977

Filed:

Oct 27, 1976

Appl. No.:

5/735991

Inventors:

Donald Dean Huizinga - Indianapolis IN
Edward William Underhill - Knightstown IN
James Arthur Whitcomb - Indianapolis IN

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04Q 518

US Classification:

179 99

Abstract:

An electronic key telephone station set includes a plurality of nonlocking line selection buttons. Adjacent each button is a pair of light emitting diode lamps, one for indicating which line selection button has been actuated and one for indicating which ones of other lines having an appearance on the station set are in use. Digital data coupled to and from the station set control the activation of the indicating lamps as well as the type of alerting signal generated to indicate an incoming call. Numerous other features may be advantageously implemented under data stream control.

Author:

Edward Bean Underhill

ISBN #:

0837137721

Author:

Edward B. Underhill

ISBN #:

0836988167