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

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.

What is claimed is:  
     
         1 . A loop integrity test device for digital subscriber line (xDSL) communication systems, the test device comprising: 
 a line interface unit operable to connect to and interface with a first point on a twisted pair telephone line, the telephone line forming a continuous electrically conductive path without intermediate components between the first point and a second point;    an output device operable to indicate a pass state and a fail state; and    a control unit comprising:    a generation unit operable to transmit a first test signature across the telephone line for reception and evaluation at the second point, the transmission of the first test signature initiating a first loop integrity test; and    an evaluation unit operable to receive a second test signature transmitted across the telephone line, the second test signature originally generated independent of the first test signature by a second loop integrity test device to initiate a second loop integrity test, the evaluation unit further operable to evaluate the second test signature to determine whether the telephone line can support xDSL communication;    the control unit operable to direct the output device to indicate a pass state if the telephone line can support DSL communication and to indicate a fail state if the telephone line can not support xDSL communication.    
     
     
         2 . The loop integrity test device of  claim 1 , wherein the second loop integrity test device couples to the telephone line at the second point and is operable to complete the first loop integrity test by receiving and evaluating the first test signature and indicating whether the telephone line can support xDSL communication based upon evaluation of the first test signature and to independently initiate the second loop integrity test by transmitting the second test signature across the telephone line.  
     
     
         3 . The loop integrity test device of  claim 1 , wherein the evaluation unit is further operable to evaluate the second test signature to determine physical characteristics of the telephone line.  
     
     
         4 . The loop integrity test device of  claim 3 , wherein physical characteristics of the telephone line comprise impedance of the telephone line.  
     
     
         5 . The loop integrity test device of  claim 3 , wherein physical characteristics of the telephone line comprise length of the telephone line.  
     
     
         6 . The loop integrity test device of  claim 1 , wherein the evaluation unit is further operable to evaluate the second test signature to determine a loss of energy across the telephone line.  
     
     
         7 . The test device of  claim 1 , wherein the generation unit is further operable to generate the first test signature using an algorithm.  
     
     
         8 . The test device of  claim 1 , wherein the output device indicates the pass state and the fail state using at least one of a light emitting diode (LED) device, an audible alarm, an electronic register that can be accessed by software, and an electronic signal provided to another component.  
     
     
         9 . The test device of  claim 1 , wherein the line interface is further operable to draw power from the telephone line sufficient to operate the test device.  
     
     
         10 . A method for local loop integrity testing of digital subscriber line (xDSL) communications, the method comprising: 
 initiating a test of a local loop telephone line by transmitting a test signature from a first point on the local loop telephone line, the local loop telephone line forming a continuous electrically conductive path without intermediate components between the first point and a second point;    receiving the test signature at the second point on the local loop telephone line;    evaluating the received test signature at the second point to determine whether the local loop telephone line can support xDSL communication; and    indicating whether the telephone line can support xDSL communication.    
     
     
         11 . The method of  claim 10 , wherein the test signature indicates initiation of the test to a device at the second point and provides sufficient information for the device to complete the test by indicating whether the telephone line can support xDSL communication.  
     
     
         12 . The method of  claim 10 , wherein evaluating is accomplished based upon changes to the test signature caused by transmission across the local loop telephone line.  
     
     
         13 . The method of  claim 10 , wherein evaluating the received test signature further comprises determining physical characteristics of the telephone line.  
     
     
         14 . The method of  claim 13 , wherein determining physical characteristics of the telephone line further comprises determining impedance of the telephone line.  
     
     
         15 . The method of  claim 13 , wherein determining physical characteristics of the telephone line further comprises determining length of the telephone line.  
     
     
         16 . The method of  claim 10 , wherein evaluating the received test signature further comprises determining a loss of energy across the telephone line.  
     
     
         17 . The method of  claim 10 , wherein indicating includes is at least one of providing a visual display of a pass state or a fail state, providing an electronic signal, and storing data in an electronic register.  
     
     
         18 . A loop integrity test device for digital subscriber line (xDSL) communication systems, the test device comprising: 
 means for initiating a test of a local loop telephone line by transmitting a test signature from a first point on the local loop telephone line, the local loop telephone line forming a continuous electrically conductive path without intermediate components between the first point and a second point;    means for receiving the test signature at the second point on the local loop telephone line;    means for evaluating the received test signature at the second point to determine whether the local loop telephone line can support xDSL communication; and    means for indicating whether the telephone line can support xDSL communication.    
     
     
         19 . The test device of  claim 18 , wherein the test signature indicates initiation of the test to a device at the second point and provides sufficient information for completing the test by indicating whether the telephone line can support xDSL communication.  
     
     
         20 . The test device of  claim 18 , wherein the means for evaluating is operable to determine at least one of impedance of the telephone line, length of the telephone line, and a loss of energy across the telephone line.  
     
     
         21 . A loop integrity test device for digital subscriber line (XDSL) communication systems, the test device comprising: 
 a line interface unit operable to connect to and interface with a first point on a twisted pair telephone line, the telephone line forming a continuous electrically conductive path without intermediate components between the first point and a second point;    an output device operable to indicate a pass state and a fail state; and    a control unit comprising:    a generation unit operable to transmit a first test signature across the telephone line for reception and evaluation at the second point by a second loop integrity test device, the transmission of the first test signature initiating a first loop integrity test, wherein the second loop integrity test device couples to the telephone line at the second point and is operable to complete the first loop integrity test by receiving and evaluating the first test signature and indicating whether the telephone line can support xDSL communication based upon evaluation of the first test signature; and    an evaluation unit operable to receive a second test signature transmitted across the telephone line, the second test signature originally generated independent of the first test signature by the second loop integrity test device to initiate a second loop integrity test independent of the first loop integrity test, the evaluation unit further operable to evaluate the second test signature to determine whether the telephone line can support xDSL communication;    the control unit operable to direct the output device to indicate a pass state if the telephone line can support DSL communication and to indicate a fail state if the telephone line can not support xDSL communication.