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Telephone Ring Eliminator

IP.com Disclosure Number: IPCOM000075958D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Georgallis, GC: AUTHOR [+3]

Abstract

Described is a circuit for eliminating or suppressing the initial rings at one or more telephones. In many instances, it is desirable to suppress the first few rings of one or more telephones in order to reduce the noise in a given area. For example, where a secretary monitors a large number of phones, it may be desirable to suppress the initial few rings at her instrument in order to allow other persons to pick up their individual phones. Thus, if one or more individuals are not available, the secretary's phone will, if provided with this suppressor, ring after one, two or three initial rings at the other instrument whereupon she may answer the phone and take a message.

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Telephone Ring Eliminator

Described is a circuit for eliminating or suppressing the initial rings at one or more telephones. In many instances, it is desirable to suppress the first few rings of one or more telephones in order to reduce the noise in a given area. For example, where a secretary monitors a large number of phones, it may be desirable to suppress the initial few rings at her instrument in order to allow other persons to pick up their individual phones. Thus, if one or more individuals are not available, the secretary's phone will, if provided with this suppressor, ring after one, two or three initial rings at the other instrument whereupon she may answer the phone and take a message.

The circuit shown will suppress a selectable number of telephone ring signals without otherwise affecting normal telephone operation. In order for the telephone ringer to operate, a 20 Hz sine-wave voltage is provided by the telephone office. This voltage is present for a two-second duration, spaced at four-second intervals. Diode CR1 allows current to flow only during the negative half of the cycle. Due to the design of the ringer, this current flow is insufficient to operate the ringer. However, capacitor C1 is charged through diodes CR2 and R1. The values of C1 and R1 determine the rate at which C1 charges. When C1 is charged sufficiently, silicon-controlled rectifier SCR 1 is turned on and maintained on for a time determined by R2 and also the rate of current drained...