Loop integrity test device and method for digital subscriber line (XDSL) communication

• US 6,366,644 B1
• Filed: 09/15/1997
• Issued: 04/02/2002
• Est. Priority Date: 09/15/1997
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Sisk, James R., McHale, John F.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Barnie, Rexford N
• Application Number:
  US08/929,778
• Time in Patent Office: 1,660 Days
• Field of Search: 379/5, 379/26, 379/27, 379/28, 379/29, 379/22-24, 379/18, 379/12, 379/10, 379/9, 379/6, 379/1, 379/1.01, 379/1.04, 379/22.02, 379/22.03, 379/22.04, 379/27.01, 379/27.03, 379/30, 370/247, 370/248, 370/249
• US Class Current: 379/1.04
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data
• CPC Class Codes: H04M 3/301 Circuit arrangements at the subscriber's side of the line
• CPC Class Codes: H04M 3/306 for frequencies above the voice frequency, e.g. xDSL line qualification test methods, test equipment and test arrangements for subscriber lines using xDSL modems H04M3/304; systems modifying transmission characteristics according to link quality H04L1/0001; monitoring and/or testing of line transmission systems H04B3/46
• CPC Class Codes: H04Q 1/028 Subscriber network interface devices

Abstract

A digital subscriber line (xDSL) communication system (10) is disclosed that allows xDSL communication across a local loop. The system (10) includes a local loop termination point (14) and customer premises equipment (12) connected to a twisted pair telephone line (16). Loop integrity test devices (22, 24) for xDSL communication are located at the local loop termination point (14) and the customer premises equipment (12) and are coupled to the telephone line (16). The loop integrity test devices (22, 24) are respectively operable to transmit test signatures across the telephone line (16), to receive and evaluate test signatures from the telephone line (16), and to indicate whether the telephone line (16) can support xDSL communication based upon evaluation of test signatures.

Claims

1. A digital subscriber line (xDSL) communication system for xDSL communication across a local loop, comprising:

a local loop termination point connected to a twisted pair telephone line;

customer premises equipment connected to the twisted pair telephone line, the telephone line forming a continuous electrically conductive path without intermediate components between the local loop termination point and the customer premises equipment;

a first loop integrity test device for xDSL communication, the first loop integrity test device located at the loop termination point and coupled to the telephone line, the first loop integrity test device operable to independently initiate a first loop integrity test by transmitting test signatures across the telephone line and to complete a second loop integrity test by receiving and evaluating test signatures transmitted by a second loop integrity test device and indicating whether the telephone line can support xDSL communication based upon evaluation of test signatures received from the second loop integrity test device; and

the second loop integrity test device located at the customer premises equipment and coupled to the telephone line, the second loop integrity test device operable to independently initiate the second loop integrity test by transmitting test signatures across the telephone line and to complete the first loop integrity test by receiving and evaluating test signatures transmitted by the first loop integrity test device and indicating whether the telephone line can support xDSL communication based upon evaluation of test signatures received from the first loop integrity test device.

2. The system of claim 1, wherein test signatures transmitted by the first loop integrity test device are the same as the test signatures transmitted by the second loop integrity test device.

3. The system of claim 1, wherein the first loop integrity test device is separate from an xDSL access multiplexer (DSLAM) located at the local loop termination point.

4. The system of claim 1, wherein the second loop integrity test device is located in a network interface device (NID) at a customer premises.

5. The system of claim 1, wherein the second loop integrity test device is located separate from a network interface device (NID) at a customer premises.

6. The system of claim 1, wherein the first and second loop integrity test devices transmit test signatures periodically.

7. The system of claim 1, wherein the first and second loop integrity test devices are further operable to generate the test signatures.

8. The system of claim 1, wherein the first and second loop integrity test devices generate the test signatures using an algorithm.

9. The system of claim 1, wherein the second loop integrity test device indicates whether the telephone line can support xDSL communication using light emitting diode (LED) devices.

10. The system of claim 1, wherein the second loop integrity test device indicates whether the telephone line can support xDSL communication using an audible alarm.

11. The system of claim 1, wherein the first loop integrity test device indicates whether the telephone line can support xDSL communication using an electronic register that can be accessed by software at the local loop termination point.

12. The system of claim 1, wherein the first loop integrity test device indicates whether the telephone line can support xDSL communication using an electronic signal provided to another component at the local loop termination point.