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:
May. 21, 1991
Filed:
Sep. 26, 1989
Yoshihiro Ashi, Yokohama, JP;
Tadayuki Kanno, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention relates to an add drop multiplexer related to the synchronous multiplexing method, and includes a pass-through line connecting unit, which is driven by a timing signal extracted from a signal received through a transmission line and effects branching and insertion of the line as well as connection of pass-through lines at multiplexed levels; an office line connecting unit having an office interface function for each of other devices in a same office; a first frame aligner connecting multiplex branched signals from the pass-through line connecting unit with the office line connecting unit; and a second frame aligner connecting multiplex inserted signals from the office line connecting unit with the pass-through line connecting unit. In this way, since the whole pass-through line connecting unit can be driven only with the timing signal extracted from the received signal from the transmission line and the frame aligner can be removed from the path of the signal through the pass-through lines, it is possible to reduce the signal delay in the pass-through lines within the add drop multiplexer.