Repeatered, multi-channel fiber optic communication network having fault isolation system

In a communication network wherein signals are conveyed between first and second stations over a plurality of communication links having at least one repeater station disposed between said first and second stations, a method for isolating a fault occurring on one of said communication links comprising the steps of:

• (a) replacing that one of said communication links on which a fault has been detected to have occurred with another of said communication links;
• (b) transmitting a first prescribed encoded signal sequence over said one of said communication links;
• (c) selectively monitoring, at respective stations along said one link, a prescribed signal transmission characteristic of said respective stations along said one link;
• and
• (d) in response to a prescribed change in the signal transmission characteristic of said link at one of said monitored stations, representative of the existence of a fault in said link at said one of said monitored stations, transmitting from said one of said monitored stations a signal representative of said change in signal transmission characteristic, so as to identify said fault or being associated with that monitored station along said link that introduces said prescribed change in said signal transmission characteristic.

In a communication network having first and second terminal stations coupled to each other over a plurality of communication links having at least one repeater station coupled in said links for regenerating information signals conveyed thereover between said first and second terminal stations, a system for controlling the operation of said network comprising:

• first means, coupled to each of said communication links, for monitoring a prescribed characteristic of signals transmitted over said links and producing a first output signal in response to a prescribed change in said characteristic on one of said links;
• second means, responsive to said first output signal produced by said first means, for replacing said one of said links with another of said links;
• third means, responsive to the replacement of said one of said links with another of said links by said second means, for causing a prescribed encoded signal sequence to be transmitted over said one of said communication links;
• fourth means, coupled to the stations along said one communication link, for monitoring a prescribed signal transmission characteristic of selected ones of said stations in response to the transmission of said prescribed encoded signal sequence over said one communication link;
• and
• fifth means, coupled to said fourth means, for identifying that station, for which there occurs a prescribed change in the monitored prescribed signal transmission characteristic in response to the transmission of said prescribed encoded signal sequence, as being associated with the prescribed change in the signal characteristic monitored by said first means that has caused said first means to produce said first output signal.

In a communication network having first and second terminal stations coupled to each other over a plurality of first communication links for conveying signals from said first terminal station to said second terminal station and a plurality of second communication links for conveying signals from said second terminal station to said first terminal station, and at least one repeater station coupled to said links for regenerating information signals conveyed over said links, a system for controlling the operation of said network comprising:

• first means, located at said first terminal station, for monitoring a prescribed characteristic of signals transmitted from said second terminal station over said second communication links to said first terminal station and producing a first output signal in response to a prescribed change in said characteristic on one of said links;
• second means, located at said first terminal station and responsive to said first output signal produced by said first means, for transmitting a first message to said second terminal station over each of said first communication links representative of the replacement of said one of of said first links by another of said first links;
• third means, located at said second terminal station and responsive to said first message from said first means, for causing signals conveyed over said one of said second links to be conveyed over another of said second links;
• fourth means, located at said first terminal station, for interrupting at said first terminal station the flow of signals conveyed over said one of said second links while enabling, at said first terminal station, the flow of said signals conveyed over said another of said second links;
• fifth means, located at said second terminal station, for inhibiting the flow of signals, which would have otherwise been conveyed over said one of said second links, at said second terminal station and causing a prescribed encoded signal sequence to be transmitted in their place.

In a communication network having first and second terminal stations coupled to each other over a plurality of communication links having at least one repeater station disposed between said first and second terminal stations, a system for controlling the operation of said network comprising:

• first means, coupled to each of said communication links, for monitoring a prescribed characteristic of signals transmitted over said links and producing a first output signal in response to a prescribed change in said characteristic on one of said links;
• second means, coupled to each of said stations, for monitoring at least one preselected operational or enviromental condition at said each station, and producing a second output signal in response to a prescribed change in said at least one preselected operational or environmental condition;
• third means, coupled to said first and second means, for replacing said one of said links with another of said links in response to said first output signal or in response to said second output signal indicating a malfunction in a condition associated with said one of said links;
• fourth means for causing a prescribed encoded signal sequence to be transmitted over said replaced one of said communication links;
• and
• fifth means, coupled to each of said stations over a communication path exclusive of said communication links, for testing the operation of selected ones of said stations in response to said prescribed encoded signal sequence.

A communication network comprising:

• a first terminal station;
• a second terminal station;
• at least one repeater station disposed between said first and second terminal stations;
• a plurality of first communication links, coupled to each of said stations, for conveying data from said first terminal station to said second terminal station;
• a plurality of second communication links, coupled to each of said stations, for conveying data from said second terminal station to said first terminal station;
• a plurality of first means, located at said first terminal station and coupled to receive data to be transmitted over respective ones of said first communications links, each of said first means including
• means for encoding data to be transmitted, and
• means for transmitting said encoded data over a respective one of said first communication links;
• a plurality of second means, located at said second terminal station and coupled to respective ones of said first communication links, for decoding encoded data that has been transmitted from said first terminal station to said second terminal station, each of said second means including
• means for receiving encoded data transmitted over a respective one of said first communication links, and
• means for decoding the received encoded data and outputting the original data;
• a plurality of third means, located at said second terminal station and coupled to receive data to be transmitted over respective ones of said second communications links, each of said third means including
• means for encoding data to be transmitted
• means for transmitting said encoded data over a respective one of said second communication links;
• a plurality of fourth means, located at said first terminal station and coupled to respective ones of said second communication links, for decoding encoded data that has been transmitted from said second terminal station to said first terminal station, each of said fourth means including
• means for receiving encoded data transmitted over a respective one of said second communication links, and
• means for decoding the received encoded data and outputting the original data;
• fifth means, located at said first terminal station, for controlling the operation of each of said first and fourth means, and coupled to each of said first and fourth means for supplying information signals to be contained in the encoded data transmitted by each of said first means and for receiving information signals contained in the encoded data decoded by each of said fourth means;
• and
• sixth means, located at said second terminal station, for controlling the operation of each of said second and third means, and coupled to each of said second and third means for supplying information signals to be contained in the encoded data transmitted by each of said third means, and for receiving information signals contained in the encoded data decoded by each of said second means;
• and wherein
• each of said encoding means includes means for encoding data to be transferred to the form of a sequence of a selected number of data bits periodically separated by a prescribed control bit, information signals from said fifth and sixth means being encoded as first preselected ones of said control bits.

In a communication network having first and second terminal stations, a plurality of information carrying normally active channels and at least one auxiliary channel linking said first and second terminal stations through at least one repeater station, the improvement comprising:

• first means for monitoring a prescribed characteristic of information signals received at the terminal station over each active one of said channels and producing a first output signal indicative of said prescribed characteristic;
• second means, coupled to said ffirst means, for causing a substitution of an auxiliary channel for that one of said normally active channels for which said first output signal from said first means indicates an unacceptable prescribed characteristic of said information signals transmitted over said one of said normally active channels;
• third means, for causing a prescribed portion of the information signals carried over said normally active channels to be conveyed through said substituted channel;
• and
• fourth means, coupled to each of said stations, for monitoring a prescribed characteristic of the prescribed portion of the information signals carried over said substituted channel, at selected ones of said stations.

A communication network comprising:

• first and second terminal stations;
• a plurality of information carrying normally active channels and an auxiliary channel linking said first and second terminal stations through at least one repeater station;
• an additional communication channel, exclusive of said normally active and auxiliary channels and over which said information signals are not carried, coupled to each of said repeater and terminal stations;
• first means for monitoring a prescribed characteristic of information signals received at a terminal station over an active one of said plurality of information carrying normally active channels and selectively causing, via one of said plurality of normally active and auxiliary channels, a substitution of said auxiliary channel for one of said normally active channels depending upon said monitored prescribed characteristic;
• and
• second means, coupled to said first means, for causing a preselected portion of said information signals to be carried over said substituted channel and for monitoring, via said additional channel, a prescribed characteristic of said preselected portion of said information signals at at least one of said stations.

In a communication network having first and second terminal stations coupled to each other over a plurality of first communication links for conveying signals from said first terminal station to said second terminal station and a plurality of second communication links for conveying signals from said second terminal station to said first terminal station, and at least one repeater station coupled in said links for regenerating information signals conveyed over said links, a system for controlling the operation of said network comprising

• first and second control apparatus, respectively located at said first and second terminal stations, each control apparatus comprising:
• first means of monitoring a prescribed characteristic of signals transmitted over the communication links from the other terminal station and producing a first output signal in response to a prescribed change in said characteristic on one of said links;
• second means, responsive to said first output signal produced by said first means, for transmitting messages to the control apparatus of the other terminal station over each of said communication links representative of the replacement of said one link which has caused the production of said first output signal by said first means;
• and
• third means, for selectively communicating with each of the stations along said links over a communication path exclusive of said communication links for selectively testing the operation of the stations along said one link.

In a communication network having first and second terminal stations coupled to each other over a plurality of first communication links for conveying signals from said first terminal station to said second terminal station and a plurality of second communication links for conveying signals from said second terminal station to said first terminal station, and at least one repeater station coupled in said links for regenerating information signals conveyed over said links, a system for controlling the operation of said network comprising:

• first and second control apparatus, respectively located at said first and second terminal stations, each control apparatus comprising:
• first means for monitoring a prescribed characteristic of signals transmitted over the communication links from the other terminal station;
• second means for selectively testing the condition and operation of each station over a communication path exclusive of said communication links;
• and
• third means, responsive to one of the detection of a prescribed change in the characteristic of monitored signals by said first means and the detection of a prescribed anomaly in the condition or operation of a selectively tested station by said second means, for communicating with the control apparatus of the other terminal station over each of said communication links and thereby causing the replacement of one of said communication links with an auxiliary communication link.