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:
Jun. 29, 1976
Filed:
May. 28, 1974
Applicant:
Inventors:
Hirotoshi Shirasu, Yokohama, JA;
Hirotaka Usuda, Yokohama, JA;
Assignee:
Hitachi, Ltd., , JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04Q / ;
U.S. Cl.
CPC ...
179 / ; 179 / ; 179 / ;
Abstract
A telephone switching system of the stored program control type comprising a calling line identifier for identifying the position of a calling subscriber on the switching network and a called line busy status detector for detecting the free or busy status of a called line designated by a central controller. The central controller reads and utilizes the information identified and detected by the above-mentioned two devices respectively, thereby to eliminate the need for memories in the central controller to store the status of all subscribers' lines.