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. 28, 1981
Filed:
Jan. 31, 1979
Tetsuo Yoshino, Tokyo, JP;
Tsuyotake Sawano, Tokyo, JP;
Nippon Electric Co., Ltd., Tokyo, JP;
Abstract
An A.C. signalling transmission trunk circuit has a single-polarity drive voltage source for controlling a pair of thyristor-switching circuits which are assigned, respectively, to a subscriber line pair. The voltage source is arranged to supply either a positive or negative half-wave A.C. signal voltage over one side of the subscriber line to one of the thyristor-switching circuits. Another half-wave A.C. drive voltage of the same polarity (but 180 degrees out of phase) is applied over the other side of the subscriber line to the other of the thyristor-switching circuits. The instantaneous potentials on the two sides of the subscriber lines have single polarity--either a positive or a negative potential--while supplying the A.C. signal to the subscriber set.