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:
Feb. 25, 1992
Filed:
Jan. 03, 1991
Koichi Nishimura, Yokohama, JP;
Ikuo Taniguchi, Yokohama, JP;
Fumihiro Ikawa, Yokohama, JP;
Masumi Kurokawa, Yokohama, JP;
Fujitsu Limited, Kanagawa, JP;
Abstract
A communication system includes a plurality of stations, a first working line coupling adjacent stations among the plurality of stations, a second working line passing predetermined stations among the plurality of stations without dropping therein, and a protection line provided in common for the first working line and the second working line, a supervisory signal always passing through the protection line. Each of the stations includes an internal circuit for receiving an input transmission signal from the first working line and sending an output transmission signal to the first working line. Each station also includes a switching portion for passing the protection line without dropping in each of the stations in a normal mode and for connecting the protection line to the internal circuit in an alarm mode so that the input transmission signal is received from an upstream side via the protection line instead of the first working line and the supervisory signal which is generated from the output transmission signal is output toward a downstream side via the protection line.