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:
Mar. 24, 1992
Filed:
Feb. 09, 1990
Hiroshi Yoshida, Kawasaki, JP;
Takashi Kihara, Zama, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An optical transmission line system includes a first optical transmission line equipment having a pair of a first optical signal transmission unit and a first optical signal reception unit, and a second optical transmission line equipment having second optical signal transmission and reception units which are connected to the first optical signal transmission and reception units through downstream and upstream optical transmission lines. When light stoppage is detected by the optical signal reception unit due to the occurrence of a disconnection or other breakage in the optical transmission lines, a corresponding optical signal transmission unit reduces the transmission level of the light transmission signal to a level harmless to the human eye. In order to reduce the level of transmission, the optical signal transmission unit converts all the main signal data bits to '0' and sends only the small number of supervisory information bits to the optical signal reception unit of the other side. The optical signal reception unit operates so as to reduce the level of transmission of the optical signal transmission unit forming a pair with that unit.