U.S. patents available from 1976 to present.
U.S. patent applications available from 2005 to present.

Dual tone multifrequency and dial pulse receiver

Patent 4460806 Issued on July 17, 1984. Estimated Expiration Date: Icon_subject May 13, 2002. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

3315039

Time shared TCMF and MF decoder
Patent #: 3941938
Issued on: 03/02/1976
Inventor: Gauthier

Microprocessor control complex for a telecommunication switching system
Patent #: 4256926
Issued on: 03/17/1981
Inventor: Pitroda ,   et al.

Time division switching system control arrangement
Patent #: 4280217
Issued on: 07/21/1981
Inventor: Hafer ,   et al.

Distributed control for digital switching system Patent #: 4317962
Issued on: 03/02/1982
Inventor: Cox ,   et al.

Inventors

Assignee

Application

No. 06/377574 filed on 05/13/1982

US Classes:

379/386, Signal receiver (e.g., tone decoder)370/526, Digital tone detection379/283, Dual tone multifrequency (DTMF) receiver379/284With processor

Examiners

Primary: Brown, Thomas W.

Attorney, Agent or Firm

International Classes

H04Q 1/457 (20060101)
H04Q 1/32 (20060101)
H04Q 1/30 (20060101)

Abstract

A dual tone multifrequency and dial pulse receiver that receives 8000 digital data words per second, each of the data words including eight PCM bits representing the analog signal transmitted from a subscriber set and also including a line status bit indicating the DC status of the line. The receiver includes a time-shared processor which processes the PCM bits of 4000 words per second to detect tone-pairs and which also processes the line status bit of 4000 words per second to detect valid dial pulse sequences. The time-shared processor stores one of a first plurality of code words in a register when a tone-pair is detected and stores one of a second plurality of code words in the register when a valid dial pulse sequence is detected. Advantageously, the receiver can detect either dual tone multifrequency or dial pulse signaling from a subscriber even though the type of signaling to be used by the subscriber is not known a priori.

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