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Remote locating system for transmission faults in data transmission line having regenerative repeaters

  • US 4,187,415 A
  • Filed: 06/05/1978
  • Issued: 02/05/1980
  • Est. Priority Date: 06/20/1977
  • Status: Expired due to Term
First Claim
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1. A remote locating system for remote locating the N pairs of regenerative repeaters which are interconnected by line sections of a bidirectional data transmission line which is interconnected between a monitoring station and a monitored station, said bidirectional data transmission line comprising;

  • a forward transmission channel, having forward transmission regenerative repeaters, conveying in the forward direction from said monitoring station to said monitored station a first data signal, anda backward transmission channel, having backward transmission regenerative repeaters, conveying in the backward direction from said monitored station to said monitoring station a second data signal;

    said monitoring and monitored stations comprising;

    means in each of said stations for detecting transmission faults on said backward and forward transmission channels; and

    means in each of said stations for producing first and second alarm signals in response to the detection of a transmission fault on said backward and on said forward transmission channels respectively;

    said monitoring station also comprising;

    a first means for continuously generating a first low frequency signal in said forward direction on said forward transmission channel in response to said first alarm signal, said first low frequency signal being mixed with said first data signal; and

    a second means for generating a second low frequency signal in said forward direction on said backward transmission channel, after said first low frequency signal is produced;

    said second low frequency signal being modulated by at most (N-1) pulses and being mixed with said first data signal on said backward transmission channel when a forward transmission regenerative repeater is connected to a backward transmission regenerative repeater;

    said forward transmission regenerative repeater of each said regenerative repeater pair comprising;

    means for detecting said first low frequency signal, andmeans for transmitting said first low frequency signal on said forward transmission channel to the next forward transmission regenerative repeater; and

    said backward transmission regenerative repeater of each said regenerative repeater pair comprising;

    means for detecting a first pulse of said second low frequency signal which is transmitted from the preceding backward transmission regenerative repeater in said forward direction on said backward transmission channel;

    means for connecting the output terminal of said forward transmission regenerative repeater to the input terminal of said backward transmission regenerative repeater in response to said detection of said first low frequency signal by said first low frequency signal detecting means,while disconnecting said input terminal of said backward transmission regenerative repeater of one pair and the output terminal of the backward transmission regenerative repeater of the next pair;

    means for disconnecting said output terminal of said forward transmission regenerative repeater of said pair from said input terminal of said backward transmission regenerative repeater of said pair in response to said detection of said first pulse of said second low frequency signal by said first pulse detection means;

    while connecting said input terminal of said backward transmission regenerative repeater of said pair and said output terminal of said backward transmission regenerative repeater of the next pair; and

    means for transmitting in said backward direction on said backward transmission channel to said output terminal of said backward transmission regenerative of said next pair, only the pulses of said second low frequency signal which succeed said first detected pulse.

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