Telecommunication system

Claim 2

A telecommunication system comprising: a first closed loop unidirectional transmission line for transmitting signals in one direction; a second closed loop unidirectional transmission line for transmitting signals in a direction opposite to said one direction; first means coupled to said first and second lines for providing on one of said first and second lines a plurality of time division multiplexed communication channel signals; and a plurality of subscriber stations coupled to said first and second lines, each of said stations including second means to connect that one of said stations to said one of said first and second lines to establish communication on an unused one of said channel signals with an idle one of said stations, third means for detecting a first fault in said one of said first and second lines, and fourth means coupled to said third means responsive to a detected first fault to interconnect said first and second lines and transfer said channel signals on said one of said first and second lines to the other of said first and second lines, said first and second lines thereby cooperating to provide a first new closed loop unidirectional transmission line to bypass said first fault; each of said stations further including fifth means coupled to said third means for generating a first alarm signal upon detection of said first fault for transmission on said one of said first and second lines; and sixth means responsive to said first alarm signal to inhibit said interconnection of said first and second lines in all of said stations except those of said stations initially detecting said first fault.

Claim 3

A system according to claim 1, wherein each of said stations further include seventh means for detecting a second fault in said other of said first and second lines; and eighth means coupled to said seventh means responsive to a detected second fault to interconnect said first and second lines and transfer said channel signals on said other of said first and second lines to said one of said first and second lines, said first and second lines thereby cooperating to provide a second new closed loop unidirectional transmission line to bypass said second fault.

Claim 4

A system according to claim 2, wherein each of said stations further include ninth means coupled to said seventh means for generating a second alarm signal upon detection of said second fault for transmission on said other of said first and second lines, and tenth means responsive to said second alarm signal to inhibit said interconnection of said first and second lines in all of said stations except those of said stations initially detecting said second fault.

Claim 5

A system according to claim 3, wherein each of said third means and seventh means includes eleventh means for generating two different signals having a predetermined relationship in the absence of any fault, twelfth means coupled to the associated one of said first and second lines for integrating and storing signals received from said associated one of said first and second lines, a first source of reference signal having a given amplitude value, thirteenth means coupled to said first source and said 12th means for comparing the amplitude value of said stored signal with said given value of said reference signal, and fourteenth means coupled to said 13th means responsive to a predetermined change between said value of said stored signal and said given value of said reference signal to reverse said predetermined relationship of said two different signals.

Claim 6

A system according to claim 4, wherein said first means further includes fifteenth means coupled to said other of said first and second lines to transmit a unique signal thereover; and each of said stations further includes a second source of signal simulating said unique signal, a monostable device coupled to said eleventh means responsive to one of said two different signals having a predetermined condition to produce an output pulse of predetermined width, and gated means coupled to said second source, said monostable device and said associated one of said first and second lines responsive to said output pulse to couple said simulated unique signal to said associated one of said first and second lines for a duration equal to said predetermined width.

Claim 7

A system according to claim 5, wherein said first means further includes sixteenth means coupled to said other of said first and second lines for detecting thereon signals normally appearing on said one of said first and second lines and producing a control signal under this condition; and seventeenth means coupled to said 16th means and said 15th means responsive to said control signal to inhibit the transmission of said unique signal and to connect said other of said first and second lines coming into said first means directly to said other of said first and second line leaving said first means as long as said control signal is present.

Claim 8

A telecommunication system comprising: a first closed loop unidirectional transmission line for transmitting signals in one direction; a second closed loop unidirectional transmission line for transmitting signals in a direction opposite to said one direction; first means coupled to said first and second lines for providing on one of said first and second lines a plurality of time division multiplexed communication channel signals; and a plurality of subscriber stations coupled to said first and second lines, each of said stations including second means to connect that one of said stations to said one of said first and second lines to establish communication on an unused one of said channel signals with an idle one of said stations, third means for detecting a first fault in said one of said first and second lines, and fourth means coupled to said third means responsive to a detected first fault to interconnect said first and second lines and transfer said channel signals to said one of said first and second lines to the other of said first and second lines, said first and second lines thereby cooperating to provide a first new closed loop unidirectional transmission line to bypass said first fault; each of said stations transmitting over said other of said first and second lines the signals also transmitted over said one of said first and second lines; and each of said stations further including fifth means coupled to said first and second lines for comparing the signals received over said one of said first and second lines from the next preceding one of said stations with the signals received over said other of said first and second lines from the next succeeding one of said stations, sixth means coupled to said fifth means for detecting a first predetermined degree of discrepancy between the compared signals, seventh means coupled to said sixth means for generating an alarm signal in response to the detection of said first discrepancy, eighth means responsive to an alarm signal generated by another one of said stations to inhibit the transmission of signals over said other of said first and second lines and to connect the incoming said other of said first and second lines to the outgoing said other of said first and second lines, ninth means coupled to said sixth means responsive to the detection of said first discrepancy to inhibit the transmission of signals over said one of said first and second lines, tenth means coupled to said first and second lines for comparing the signals received over said one of said first and second lines with the signals received over said other of said first and second lines, eleventh means coupled to said 10th means for detecting a second different predetermined degree of discrepancy between the signals compared in said 10th means; and twelfth means coupled to said 11th means responsive to the detection of said second discrepancy to transfer signals received over said other of said first and second lines to said one of said first and second lines, said 12th means being inhibited when said second discrepancy is no longer detected.

Claim 9

A telecommunication system comprising: a first closed loop unidirectional transmission line for transmitting signals in one direction; a second closed loop unidirectional transmission line for transmitting signals in a direction opposite to said one direction; first means coupled to said first and second lines for providing on one of said first and second lines a plurality of time division multiplexed communication channel signals; and a plurality of subscriber stations coupled to said first and second lines, each of said stations including second means to connect that one of said stations to said one of said first and second lines to establish communication on an unused one of said channel signals with an idle one of said stations, third means for detecting a first fault in said one of said first and second lines, and fourth means coupled to said third means responsive to a detected first fault to interconnect said first and second lines and transfer said channel signals to said one of said first and second lines to the other of said first and second lines, said first and second lines thereby cooperating to provide a first new closed loop unidirectional transmission line to bypass said first fault; each of said stations transmitting over said other of said first and second lines the signals also transmitted over said one of said first and second lines; and each of said stations further including fifth means coupled to said first and second lines for comparing the signals received over said one of said first and second lines from the next preceding one of said stations with the signals received over said other of said first and second lines from the next succeeding one of said stations, sixth means coupled to said fifth means for detecting a first predetermined degree of discrepancy between the compared signals, seventh means coupled to said sixth means for generating an alarm signal in response to the detection of said first discrepancy, eighth means responsive to an alarm signal generated by another one of said stations to inhibit the transmission of signals over said other of said first and second lines and to connect the incoming said other of said first and second lines to the outgoing said other of said first and second lines, ninth means coupled to said sixth means responsive to the detection of said first discrepancy to inhibit the transmission of signals over said one of said first and second lines, tenth means coupled to said first and second lines for comparing the signals received over said one of said first and second lines with the signals received over said other of said first and second lines, eleventh means coupled to said 10th means for detecting a second different predetermined degree of discrepancy between the signals compared in said 10th means; and twelfth means coupled to said 11th means responsive to the detection of said second discrepancy to transfer signals received over said other of said first and second lines to said one of said first and second lines, said 12th means being inhibited when said second discrepancy is no longer detected.

Claim 10

A system according to claim 7, wherein each of said stations further includes thirteenth means coupled to said 11th means responsive to the detection of said second discrepancy for generating an alarm signal.

Claim 11

A system according to claim 8, wherein each of said thirteenth means includes fourteenth means coupled to said eleventh means for inhibiting the generation of said alarm signal for a given period of time after the detection of said second discrepancy.