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.:
Date of Patent:
Jul. 14, 1987
Filed:
Mar. 28, 1986
Applicant:
Inventors:
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04J / ;
U.S. Cl.
CPC ...
3701102 ;
Abstract
A switching system having a tone trunk which stores, in the digital memory thereof, a predetermined digital tone signal in the form of digital codes for supplying the corresponding analog tone signal to telephone sets of subscribers. The digital codes have been coded in such a way that the analog tone signal is accompanied by a quantizing noise having a characteristic of white noise.