Browse Prior Art Database

On Hook Off Hook Detector in Digital Telephone Set

IP.com Disclosure Number: IPCOM000078616D
Original Publication Date: 1973-Feb-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Besseyre, J: AUTHOR

Abstract

In an analog telephone set, the ON hook/OFF hook function is performed through mechanical assembly and the hook switch has several functions. In a digital telephone set which is loop connected, most of the functions of the hook switch are performed by logic integrated circuits and one of the functions left to the hook switch is the idle/busy indication.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

On Hook Off Hook Detector in Digital Telephone Set

In an analog telephone set, the ON hook/OFF hook function is performed through mechanical assembly and the hook switch has several functions. In a digital telephone set which is loop connected, most of the functions of the hook switch are performed by logic integrated circuits and one of the functions left to the hook switch is the idle/busy indication.

The DC current in a loop connected telephone set is permanent, since the telephone set acts as a repeater and regenerates the signals whatever the ON hook/OFF hook status of the telephone set may be. The function: establish or suppress the DC current in a digital telephone set which is loop connected is thus suppressed.

It is presently proposed that the ON hook/OFF hook status of such a telephone set be detected through a Hall effect detector D. Detector D is positioned on the telephone set T and a rubber magnet M is fixed on the inside face of handset H. Detector D is designed to generate a signal upon displacement of magnet M, indicating ON/OFF hook status of handset H.

It is also possible to place detector D inside the telephone set, and magnet M on a lever arrangement, which is actuated by handset H and causes the displacement of magnet M in relation to detector D.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]