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

• Current Assignee: Etat Francaise, Societe Anonyme de Telecommunications (Safran SA)
• Original Assignee: Etat Francaise, Societe Anonyme de Telecommunications (Safran SA)
• Inventors: Boutmy, Patrick E., Camborde, Jean-Marc A.
• Primary Examiner(s): Konick, Bernard
• Assistant Examiner(s): Popek, Joseph A.
• Application Number:
  US05/912,727
• Time in Patent Office: 610 Days
• Field of Search: 179/175.3 F, 179/175.31, 179/175.3 R, 179/15 BF
• US Class Current: 370/243
• CPC Class Codes: H04B 17/408 using successive loop-backs

Abstract

A remote locating system for remote locating the pairs of regenerative repeaters of a bidirectional data transmission line which is interconnected between a monotoring station and a monitored station. The monitoring station comprises a first low frequency generator which generates a first low frequency signal on the forward line channel which is continuously transmitted in the forward direction from the monitoring station to the monotored station in response to the fault detection on the line and a second low frequency generator which generates a second low frequency signal on the backward line channel which is transmitted in the forward direction after the transmission beginning of the first signal. The second signal is modulated by successive pulses, each of which identifies a regenerative repeater pair. The first signal is simultaneously detected in each forward transmission regenerative repeater and controls the connection of the output and the input of the forward and backward transmission regenerative repeaters of each pair. In the backward transmission regenerative repeater of each pair the pulse which identifies the next pair, is detected for connecting the input and the output of the backward regenerative repeaters of the pair and the next pair and for disconnecting the regenerative repeaters of the pair. The first and second low frequency signals are mixed with a digital testing signal which is transmitted from the monitoring station through the connected pair and is monitored between two successive pulses so as to detect the transmission faults of the connected pair or the connected line section.

Claims

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, and

a 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, and

means 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.

2. A remote locating system as claimed in claim 1, in which in each said regenerative repeater pair, said first low frequency signal detecting means and said connecting means are connected, by an opto-electronic coupler which converts said first low frequency signal to a direct current signal and which electrically insulates the two regenerative repeaters of said pair.

3. A remote locating system as claimed in claim 1 in which the first pulse detected in the backward transmission regenerative repeater of an ith regenerative repeater pair, where i is between 1 and N, is the ith pulse which is produced by said second generating means.

4. A remote locating system as claimed in claim 1 in which said low frequency signal detecting means of the forward transmission regenerative repeater of each of said regenerative repeater pairs controls the interruption of the remote supply of said connecting means, when said first generating means does not generate said first low frequency signal, and said connecting means and transmitting means of said backward transmission regenerative repeater of said regenerative repeater pair provides the disconnection between the forward and backward transmission channels in all regenerative repeater pairs.

5. A remote locating system as claimed in claim 1 in which said first alarm signal producing means produces a first alarm indication signal on the output data transmission channels of other lines which are connected to said monitoring station and said second alarm signal producing means produces a second alarm indication signal on the output data transmission channels of other lines which are connected to said monitored station in response to a transmission fault by said first or second transmission fault detecting means.