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. 03, 1987
Filed:
Mar. 07, 1985
Andrew Dean, Stansted, GB;
International Standard Electric Corporation, New York, NY (US);
Abstract
In a local area network (LAN), of the Ethernet type, one of the segments, i.e. one bus, is replaced by a star coupler connected via optical fibre pairs to a number of stations. Each pair includes a GO fibre and a RETURN fibre. As in the usual Ethernet system, collision detection relies on measuring signal level on the medium, if it is too large then a collision condition exists. In an optical fibre system a similar collision detection technique is used. To detect collision, it is nescessary to be aware of the network's attenuation as 'seen' by the station. To do this a low level pilot tone is sent from each station, each station having its own tone frequency. The amplitude of this tone when it returns to its own station indicates the system's attenuation, and this is used to detect collision. In an alternative the pilot signals are pseudo-random bit sequences.