# US 5,710,777 A · Communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,710,777 A - Document ID: US5710777A - Status: Granted - Kind: A - Application number: 08/014,258 - Filed: 1993-02-05 - Granted: 1998-01-20 - Earliest claimed: 1992-02-07 - Assignees: Madge Networks Limited - Inventors: Simon C. Gawne - Web page: https://patentgrep.com/patent/US5710777A ## CPC - H04L 43/50: Testing arrangements - G06F 11/22: Detection or location of defective computer hardware by testing during standby operation or during idle time, e.g. start-up testing - H04L 12/42: Loop networks - H04L 12/433: with asynchronous transmission, e.g. token ring, register insertion - H04L 12/437: Ring fault isolation or reconfiguration {(for SDH/SONET ring networks H04J3/085)} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A method of analysing a communication system to locate the source of a fault. The communication system comprises a signal carrying medium (9) coupled to a series of end station ports (2-6) which enable respective end stations (24) to transmit signals onto and receive signals from the medium and a controller (8) to control connection of end stations (24) to the medium via the ports (2-6). The method comprises disconnecting end stations (24) in series from the medium (9) in response to detection of a fault and then detecting whether the fault still exists. A fault analyzer (10) adapted to respond to the detection of a fault causes the controller (8) firstly to disconnect an end station (24) which has previously been characterised as the most likely source of a fault. The controller (8) may disconnect groups of end stations (24) and reconnect subgroups if no fault is present in the group which was not disconnected until the faulty end station is identified. ## Claims ### Claim 1 A method of analysing a communication system to locate a source of a fault, the communication system comprising a signal carrying medium coupled to a series of end station ports which enable respective end stations to transmit signals onto and receive signals from said signal carrying medium; and control means for controlling a connection of end stations to said signalling carrying medium via said end station ports, the method comprising the steps of: upon detection of a fault, disconnecting end stations in series from said signal carrying medium; detecting whether or not a fault condition still exists; and causing said control means firstly to disconnect an end station which has previously been characterised as the most likely to be the source of the fault, under control of fault analysis means adapted to respond to fault detection. ### Claim 2 (depends on 1) A method according to claim 1, wherein a first end station to be disconnected is one of the most recent end station to have been connected to the communication system and the last end station which has been diagnosed as causing a fault. ### Claim 3 A method of analysing a communication system to locate a source of a fault, the communication system comprising a signal carrying medium coupled to a series of end station ports which enable respective end stations to transmit signals onto and receive signals from said signal carrying medium; and control means for controlling a connection of said respective end stations to the medium via the ports, the method comprising the steps of: a) causing said control means to disconnect a group of said end stations; b) detecting whether the fault exists; c) i) if it does, disconnecting a group of remaining end stations, or ii) if it does not, reconnecting a number of end stations of a previously disconnected group; d) detecting whether the fault exists; and, e) repeating steps (c) and (d) until the end station causing the fault is located. ### Claim 4 (depends on 3) A method according to claim 3, wherein the group of stations which are disconnected at each stage is substantially half of the remaining end stations. ### Claim 5 A communication system comprising: a signal carrying medium coupled to a series of end station ports which enable respective end stations to transmit signals onto and receive signals from said signal carrying medium; control means for controlling a connection of end stations to said signal carrying medium via said end station ports; and fault analysis means for detecting a source of a fault on the system, the fault analysis means being adapted to carry out a method comprising the steps of: upon detection of a fault, disconnecting end stations in series from said signal carrying medium; detecting whether or not a fault condition still exists; and causing said control means firstly to disconnect an end station which has previously been characterised as the most likely to be a source of the fault, under control of fault analysis means adapted to respond to fault detection. ### Claim 6 (depends on 5) A system according to claim 5, wherein said control means and fault analysis means are provided within a concentrator unit and are defined at least in part by a suitably programmed microprocessor. ### Claim 7 (depends on 5) A system according to claim 5, wherein the system is a ring communication system. ### Claim 8 A communication system comprising: a signal carrying medium coupled to a series of end station ports which enable respective end stations to transmit signals onto and receive signals from said signal carrying medium; control means for controlling connection of end stations to said signal carrying medium via said end station ports; and fault analysis means for detecting a source of a fault on the system, the fault analysis means being adapted to carry out a method comprising the steps of: a) causing said control means to disconnect a group of said end stations; b) detecting whether the fault exists; c) i) if it does, disconnecting a group of remaining end stations, or ii) if it does not, reconnecting a number of end stations of a previously disconnected group; d) detecting whether the fault exists; and, e) repeating steps (c) and (d) until the end station causing the fault is located. ### Claim 9 (depends on 8) A system according to claim 8, wherein said control means and fault analysis means are provided within a concentrator unit and are defined at least in part by a suitably programmed microprocessor. ### Claim 10 (depends on 8) A system according to claim 8, wherein the system is a ring communication system.