Ground key detection circuit and method for...

Details Ground key detection circuit and method for... Ground key detection circuit and method for...

2005-09-13

2005-09-13

Tieu, Binh (Department: 2643)

Telephonic communications

Substation or terminal circuitry

C379S377000, C379S382000, C379S416000

Reexamination Certificate

active

06944286

ABSTRACT:
A grounding key detecting device and method for interference-proof detection of the operation of grounding keys in telephones. A circuit that detects the operation of a grounding key includes a current detection device configured to detect a current flowing when the grounding key is in operation, a comparator configured to compare the detected current with at least one threshold value, and a monitoring circuit configured to detect a first period when the current exceeds the threshold value, detect a second period when the current drops below the threshold value, and output a grounding key detection signal when the first period is greater than the second period.

REFERENCES:
patent: 4156797 (1979-05-01), Hoole
patent: 4320260 (1982-03-01), Lechner
patent: 5048080 (1991-09-01), Bell et al.
patent: 5511118 (1996-04-01), Gores et al.
patent: 5515417 (1996-05-01), Cotreau
patent: 5517565 (1996-05-01), Cotreau
patent: 5596637 (1997-01-01), Pasetti et al.
patent: 5659570 (1997-08-01), Correau et al.
patent: 5774316 (1998-06-01), McGary et al.
patent: 05-292158 (1993-11-01), None

Affiliated with

Also associated with

Rating

Ground key detection circuit and method for... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Ground key detection circuit and method for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ground key detection circuit and method for... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3431894