Signal detector for telephone line repeator remote loopback system

• US 5,726,993 A
• Filed: 08/19/1996
• Issued: 03/10/1998
• Est. Priority Date: 10/25/1995
• Status: Expired due to Term

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: Siemens Telecom Networks (Siemens AG)
• Inventors: Kelsey, Karl A., Bailey, Romuald
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Elmore, Stephen C.
• Application Number:
  US08/699,377
• Time in Patent Office: 568 Days
• Field of Search: 371/20.2, 370/243, 370/246, 370/248, 370/249, 370/253, 379/4, 379/5, 379/26, 379/27
• US Class Current: 714/713
• CPC Class Codes: H04B 17/408 using successive loop-backs
• CPC Class Codes: H04B 3/46 Monitoring; Testing

Abstract

A loopback enabled by an instruction and address code pair transmitted with the regular data stream affords a simplified fault location scheme for a T1 repeater span. By selecting unique addresses for each repeater using a predetermined frame sequence and by testing for logic error density, erroneous enablement is avoided.

Claims

1. A repeater having a unique address designation, wherein the repeater comprises:

first detection means for detecting a first inchannel signal, the first inchannel signal being representative of an enabling command;

enabling means, responsive to the first detection means, for enabling the detection of a second inchannel signal, the second inchannel signal being representative of the unique address designation;

second detection means, responsive to the enabling means, for detecting the second inchannel signal; and

means, responsive to the second detection means, for initiating a loopback.

2. A repeater as set forth in claim 1, further comprising

third detection means for detecting a third inchannel signal, the third inchannel signal being representative of a disabling command;

and

means, responsive to the third detection means, for disabling the loopback.

3. A repeater as set forth in claim 2, wherein the inchannel signals are code sequences.

4. A repeater as set forth in claim 1, wherein

the means for enabling comprises means for determining whether the detected first inchannel signal is valid;

and

the second detection means comprises means for determining whether the detected second inchannel signal is valid.

5. A repeater as set forth in claim 4, wherein

the means for determining whether the detected first inchannel signal is valid comprises means for determining whether the first inchannel signal is present for at least a predetermined interval of time;

and

the means for determining whether the detected second inchannel signal is valid comprises means for determining whether the second inchannel signal is present for at least a predetermined interval of time.

6. A repeater as set forth in claim 5, wherein the means for determining whether the detected second inchannel signal is valid further comprises means for determining whether the second inchannel signal is detected within a predetermined interval of time.

7. A repeater as set forth in claim 5, wherein

the means for determining whether the detected first inchannel signal is valid further comprises means for detecting errors in the detected first inchannel signal;

and

the means for determining whether the detected second inchannel signal is valid further comprises means for detecting errors in the detected second inchannel signal.

8. A repeater as set forth in claim 7, wherein each of the means for detecting errors comprises means for determining the density of errors in the detected signals.

9. A signal detector for a repeater having a unique address designation, comprising:

first detection means, responsive to inchannel signals, for detecting a first inchannel code sequence, the first inchannel code sequence being representative of an enabling command;

enabling means, responsive to the first detection means, for enabling the detection of a second inchannel code sequence, the second inchannel code sequence being representative of the unique address designation, where the means for enabling comprises

means for determining whether the first inchannel code sequence is present for at least a predetermined interval of time; and

means for determining the density of errors in the detected first inchannel code sequence;

second detection means, responsive to the enabling means and inchannel signals, for detecting the second inchannel code sequence, where the second detection means comprises

means for determining whether the second inchannel code sequence is detected within a predetermined interval of time;

means for determining whether the second inchannel code sequence is present for at least a predetermined interval of time; and

means for determining the density of errors in the detected second inchannel code sequence;

means, responsive to the second detection means, for initiating a loopback;

third detection means for detecting a third inchannel code sequence, the third inchannel code sequence being representative of a disabling command, where the third detection means comprises means for determining the density of errors in the detected third inchannel code sequence; and

means, responsive to the third detection means, for disabling the loopback.

10. A method for initiating a loopback in a repeater in response to inchannel signals, where the repeater has a unique address designation, comprising the steps of:

detecting a first inchannel signal, the first inchannel signal being representative of an enabling command;

in response to the step of detecting a first inchannel signal, enabling the detection of a second inchannel signal, the second inchannel signal being representative of the unique address designation;

in response to the step of enabling, detecting the second inchannel signal; and

in response to the step of detecting the second inchannel, initiating a loopback.

11. A method as set forth in claim 10, further comprising the steps of

detecting a third inchannel signal, the third inchannel signal being representative of a disabling command;

and

disabling the loopback in response to the step of detecting a third inchannel signal.

12. A method as set forth in claim 11, wherein the inchannel signals are code sequences.

13. A method as set forth in claim 10, wherein

the step of enabling the detection of a first inchannel signal comprises the step of determining whether the detected first inchannel signal is valid;

and

the step of detecting the second inchannel signal comprises the step of determining whether the detected second inchannel signal is valid.

14. A method as set forth in claim 13, wherein

the step of determining whether the detected first inchannel signal is valid comprises the step of determining whether the first inchannel signal is present for at least a predetermined interval of time;

and

the step of determining whether the detected second inchannel signal is valid comprises the step of determining whether the second inchannel signal is present for at least a predetermined interval of time.

15. A method as set forth in claim 14, wherein the step of determining whether the detected second inchannel signal is valid comprises the step of determining whether the second inchannel signal is detected within a predetermined interval of time.

16. A method as set forth in claim 14, wherein

the step of determining whether the detected first inchannel signal is valid further comprises the step of detecting errors in the detected first inchannel signal;

and

the step of determining whether the detected second inchannel signal is valid further comprises the step of detecting errors in the detected second inchannel signal.

17. A method as set forth in claim 16, wherein the steps of detecting errors in the detected signals each comprise the step of determining the density of errors in the detected signals.

18. A method of detecting signals for initiating a loopback in a repeater having a unique address designation, comprising:

detecting a first inchannel code sequence, the first inchannel code sequence being representative of an enabling command;

enabling the detection of a second inchannel code sequence, the second inchannel code sequence being representative of the unique address designation, where the step of enabling comprises the steps of

determining whether the first inchannel code sequence is present for at least a predetermined interval of time; and

determining the density of errors in the first inchannel detected code sequence;

detecting the second inchannel code sequence, where the step of detecting the second inchannel code comprises the steps of

determining whether the second inchannel code sequence is detected within a predetermined interval of time;

determining whether the second inchannel code sequence is present for at least a predetermined interval of time; and

determining the density of errors in the detected second inchannel code sequence;

in response to the step of detecting the second inchannel code sequence, initiating a loopback;

detecting a third inchannel code sequence, the third inchannel code sequence being representative of a disabling command, where the step of detecting a third inchannel code sequence comprises the step of determining the density of errors in the detected third inchannel code sequence; and

disabling the loopback in response to the step of detecting a third inchannel code sequence.

19. A signal detector for a repeater having a unique address designation and being responsive to inchannel code sequences comprising wake-up, address, and loopdown codes, the signal processor comprising:

code detection logic comprising

wake-up code detection logic for detecting the wake-up code;

address code detection logic for detecting the address code; and

loopdown code detection logic for detecting the loopdown code;

timing logic comprising

a first timer for determining whether a detected inchannel code sequence is present for at least a predetermined interval of time;

a second timer for determining whether the address code is received within a predetermined time interval; and

a third timer for determining whether the duration of a loopback has exceeded a predetermined time interval;

error density counter logic for determining the density of errors in a detected inchannel code sequence; and

a state machine comprising

first state means, responsive to the wake-up code detection logic, for enabling the first timer and the error density counter logic;

second state means, responsive to the first state means, the first timer, and the error density counter logic, for enabling the second timer;

third state means, responsive to the address code detection logic, the first and second timers, and the error density counter logic, for initiating a loopback and enabling the third timer; and

fourth state means, responsive to the third timer, the loopdown code detection logic, and the error density counter logic, for disabling the loopback.