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:
Apr. 04, 1978
Filed:
Oct. 22, 1974
Applicant:
Inventor:
Shinzi Okuhara, Fujisawa, JA;
Assignee:
Hitachi, Ltd., , JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04Q / ;
U.S. Cl.
CPC ...
179 / ; 3401 / ;
Abstract
A plurality of sets of thyristors, each set consisting of two thyristors connected in inverse parallel configuration, are arranged in the form of a matrix to provide a switch of balanced or unbalanced type. A control circuit is provided which feeds successive pulses or light energy whose repetition rate is higher than the frequency of the ac signal such as a ringing signal passing through the speech paths, to the thyristors at a cross-point to be closed, during the time required for exchange operation. In this way, a speech path switch can be constituted of semiconductor elements and ringing, dialing and hooking signals can be treated together with speech signals.