Browse Prior Art Database

Progress Tone Card

IP.com Disclosure Number: IPCOM000042941D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Brady, RL: AUTHOR [+4]

Abstract

This module, which is useful for generating and detecting tone signals associated with telephony (refer to Electronic Industries Association RS-64 Standard, and American Telephone and Telegraph Company's "Notes On the Network"), can be packaged on a single 7-inch by 9-inch integrated circuit card and used in intelligent PABX switching systems described in (1,2,3). It operates over a bandwidth from 250 Hz to 4KHz (approximate), and can also be used for detecting voice energy and not-standard tones. As shown in the illustration, the module contains a tone generation section 1 and a tone detection section 2. The tone generation section contains four low-distortion sine-wave oscillators 3 for generating basic frequencies of 350 Hz, 440 Hz, 480 Hz, and 620 Hz.

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Progress Tone Card

This module, which is useful for generating and detecting tone signals associated with telephony (refer to Electronic Industries Association RS-64 Standard, and American Telephone and Telegraph Company's "Notes On the Network"), can be packaged on a single 7-inch by 9-inch integrated circuit card and used in intelligent PABX switching systems described in (1,2,3). It operates over a bandwidth from 250 Hz to 4KHz (approximate), and can also be used for detecting voice energy and not-standard tones. As shown in the illustration, the module contains a tone generation section 1 and a tone detection section 2. The tone generation section contains four low-distortion sine-wave oscillators 3 for generating basic frequencies of 350 Hz, 440 Hz, 480 Hz, and 620 Hz. These frequencies are combined in various combinations in a mixing network 4. Mixers 4 supply pairs of frequencies to switches 5 which are selected and turned on and off at repetition rates and duty cycles governed by timing circuit 6. The timer digitally synthesizes the various timing programs required using a reference frequency supplied by crystal oscillator 7. Output stage 8 contains low output impedance power amplifiers for simultaneously driving multiple telephone devices to produce the indicated audible tones. Under the direction of not shown selection control circuits (not shown). The outputs of amplifiers 8 are applied to user telephone instruments through switching units (not shown). The selection control circuits and switching units are directed by commands supplied by a data processing system (not shown) which supervises the above-mentioned PABX (a...