Invalidity dossier
US 5535035
Optical fiber ring communications system and communications method
Current assignee: International Business Machines Corp
Added 9/23/2026, 5:58:52 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
US5535035A — Patent Overview
Title: Optical fiber ring communications system and communications method
Patent number: US5535035A
Application number: US08/306,560
Inventors: Steven M. DeFoster; Horst L. Truestedt; Raymond J. Thatcher
Original/current assignee: International Business Machines Corp. (IBM), Armonk, N.Y.
Priority/filing date: 1994-09-15
Publication (grant) date: 1996-07-09
Legal status: Expired – Fee Related; anticipated expiration 2014-09-15 (status as listed is an assumption, not a legal conclusion)
Classification: H04B10/27, H04B10/275 (ring-type networks)
Purpose: The invention relates generally to a multiple-node ring communications system, and more particularly to an optical fiber multiple-node ring system using a dual optical fiber between nodes, plus a communications method. A stated principal object is an improved method and system with multiple devices, a pair of optical fibers between adjacent devices, and a pair of optical link modules (OLMs) connected to a single port of each device. Other objects are to avoid negative effects and overcome disadvantages of prior arrangements.
Plain-language scope (from the supplied text): Each port uses a pair of shortwave-laser OLMs, with dual optical fibers between adjacent ports. During normal operation the two fibers define dual fiber channel arbitrated loops (FCALs), providing higher performance/bandwidth and redundancy. Each OLM sends a closed-link test signal to its adjacent port's receiver and waits for it to be sent back, maintaining optical fiber control (OFC) laser-safety functionality. The system tolerates a single fault (e.g., a broken fiber link): it can operate as a single arbitrated loop, or as two smaller loops coupled by a "ruler port," with "subject ports." Ports 1–N include a port path select block for selective intraport paths. The disclosure references the IBM OLM-531 Optical Link Module.
Source: https://patents.google.com/patent/[US5535035](/patent/US5535035)/en
What the excerpt does not establish: The full claim set and their exact scope; complete specification text (excerpt only, text omitted); prosecution history; the precise operation of the ruler/subject port protocol (FIG. 5 sequence chart not reproduced); and any details beyond the figures and passages provided.
Generated 10/1/2026, 9:43:07 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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