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The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Patent No.:

US 4585909 B1

PDFFull Text
Date of Patent:
Apr. 29, 1986

Filed:

Mar. 28, 1984

Transmission circuit for a dtmf-telephone set

Applicant:
Inventors:

Henricus J Otten, Eindhoven, NL;

Frederik Van Dongen, Eindhoven, NL;

Josephus J Geboers, Eindhoven, NL;

Assignee:

U.S. Philips Corporation, New York, NY (US);

Attorneys:

Briody; Thomas A.

Streeter; William J.

Eason; Leroy

Primary Examiner:

James L Dwyer

Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
179 / ;
Abstract

Transmission circuit for a telephone set for DTMF-tone selection. The required second-order tone filter is formed by arranging the speech filter (12) during the dialling procedure in series with a fixed first-order tone filter (10) by means of a switch (11). The resultant attenuation of the group II of high frequencies of the dialling tones is compensated for by increasing the amplitude of the dialling tones of the high-frequency group II and by an additional increase in the sub-group II(2) of the two highest frequencies of this group.

Find Patent Forward Citations

Otten, Henricus. (1986). Transmission circuit for a dtmf-telephone set (U.S. Patent No. 4585909). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/4585909

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

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