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US 5,553,059 AGranted
Network interface unit remote test pattern generation
AssigneeIntegrated Network Corporation
InventorsEarl A. Emerson, Henry J. Gonzalez, Kyung-Yeop Hong
Life of this patent
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Abstract
A system for isolating the direction of communication errors in the local loop of a digital data network is described. A Network Interface Unit (NIU) located at the customer premises typically has a loopback feature, allowing for Bit Error Rate Tests (BERT) to be performed on the local loop from a remote test system located on the data network. The NIU loopback test isolates transmission problems at the customer premises from problems on the local loop. The present invention adds test pattern generation capability to the NIU, allowing the remote test system to determine whether the transmission problem on the local loop is in the network to customer premises direction or in the customer premises to network direction.
Claims30
An apparatus for coupling to a local loop of a digital communication channel having first and second directions of transmission comprising:
- a) a monitor circuit for monitoring said communication channel for a digital control command transmitted from a remote test system in said first direction of transmission;
- said control command comprising a generate-pattern command or a loopback-test command;
- b) a loopback circuit for receiving digital test signals transmitted by said test system in said first direction of transmission and for returning said digital test signals to said test system in said second direction of transmission in response to said loopback-test command;
- and wherein the digital test signals that are returned are used by said test system to determine if communication errors occur in either said first or said second directions of transmission;
- and
- c) a pattern-generation circuit for generating a plurality of predetermined digital test data sequences which are transmitted to said test system over said communication channel in said second direction of transmission in response to said generate-pattern command;
- and wherein said test data sequences are used by said test system to determine if communication errors occur in said second direction of transmission.
4 more elements
A method of testing a local loop of a digital communication system having a first direction and a second direction of transmission comprising the steps of:
- a) generating a digital control command at a network test system for transmission in the first direction;
- said control command comprising a generate-pattern command or a loopback-test command;
- b) receiving the control command at an interface unit;
- c) responding to a loopback-test command at said interface unit by receiving digital test signals transmitted by said test system in said first direction of transmission and returning said digital test signals to said test system in said second direction of transmission;
- wherein said test system determines if communication errors occur in either the first or second directions of transmission;
- and
- responding to a generate-pattern command by generating a digital test data sequence at said interface unit and transmitting said test data sequence in said second direction to said network test system;
- said network test system determining if communication errors occur in the second direction of transmission.
5 more elements
A method of isolating the direction of communication errors in a local loop of a digital communication channel comprising the steps of:
- a) generating a digital control command comprising a loopback-test command or a generate-pattern command at a network test system;
- b) communicating said control command to an interface unit coupled to the communication channel;
- c) responding to a loopback-test command at the interface unit by receiving digital test signals transmitted by said test system and returning said digital test signals to said test system;
- said test system determining if communication errors occur on the communication channel in either direction of transmission between said test system and said interface unit;
- and
- d) responding to a generate-pattern command at the interface unit by generating a digital test data sequence and transmitting said test data sequence over said communication-channel to said network test system;
- said network test system determining if communication errors occur in a direction of transmission from said interface unit toward said test system.
4 more elements
A method of isolating the direction of communication errors in a local loop of a digital communication system comprising the steps of:
- a) generating digital control commands and test data at a network test system for transmission in a first direction over a first two-wire pair;
- and
- b) responding to said control commands by generating a digital test data sequence and transmitting said test data sequence in a second direction over a second two-wire pair to said network test system for use by said network test system in determining if errors in communication occur in the second direction.
An apparatus comprising:
- a) a monitor circuit for monitoring a local loop of a digital communication channel having first and second directions of transmission for a digital control command transmitted from a remote test system in said first direction of transmission;
- said control command comprising a generate-pattern command or a loopback-test command;
- a loopback circuit for receiving digital test signals transmitted by said test system in said first direction of transmission and for returning said digital test signals to said test system in said second direction of transmission in response to said loopback-test command;
- said returned test signals being used by said test system to determine if communication errors occur in either said first or said second directions of transmission;
- and
- c) pattern-generation circuit for generating a plurality of predetermined digital test data sequences which are transmitted to said test system over said communication channel in said second direction of transmission in response to said generate-pattern command for use by said test system in determining if communication errors occur in said second direction of transmission.
3 more elements
A system comprising:
- a) a digital communication channel for communicating data in first and second directions;
- b) a network test unit coupled to said communication channel for sending a digital control command in said first direction and for receiving test data in said second direction;
- said control command comprising a loopback-test command or a generate-pattern command;
- and
- c) an interface unit coupled to said communication channel for receiving said control command, said interface unit responding to said loopback-test command by receiving digital test signals transmitted by said test system in said first direction and by returning said digital test signals to said test system in said second direction, said test system determining if transmission errors occurred in either said first or said second direction;
- said interface unit responding to said generate-pattern command by generating a digital test data sequence for transmission in said second direction, said network test unit receiving said test data sequence and determining if transmission errors occurred in said second direction.
3 more elements
A system comprising:
- a) a network test system for generating a digital control command and digital test signals, and for inspecting digital test data sequences and said digital test signals to determine if transmission errors occur;
- said digital control command comprising a loopback-test command or a generate-pattern command;
- b) a digital communication channel for communicating data in first and second directions;
- c) a communication unit coupled to said digital communication channel for transmitting said control command and said digital test signals in said first direction, and for receiving said returned test data sequences and said digital test signals in said second direction;
- and
- d) an interface unit coupled to said digital communication channel;
- said interface unit responding to said loopback-test command by receiving said digital test signal transmitted by said network test system through said communication unit in said first direction and by returning said digital test signals to said network test system through said communication unit in said second direction, said test system determining if transmission errors occurred in either said first or said second directions;
- said interface unit responding to said generate-pattern command by generating predetermined test data sequences and transmitting said test data sequences over said digital communication channel in said second direction, said test data sequences being received by said communication unit and inspected by said network test system, said network test system determining if transmission errors occurred in said second direction.
5 more elements
A system comprising:
- a) a communication unit for transmitting digital information in a first direction over a first pair of lines and receiving digital information in a second direction over a second pair of lines, said pairs of lines forming a local loop coupled to a communication network;
- b) an interface unit for interfacing with said local loop;
- c) a network test system for generating digital control commands for transmission over said first pair of lines by said communication unit and for inspecting test data sequences received by said communication unit over said second pair of lines;
- and
- d) a circuit for responding to said control commands on said first pair of lines by generating digital test data sequences and sending said test data sequences over said second pair of lines.
2 more elements
A system comprising:
- a) a digital communication channel for communicating data in first and second directions;
- b) a network test unit coupled to said communication channel for sending a digital control command and digital test signals in said first direction and for receiving digital test data sequences and digital test signals in said second direction, said control command comprising a loopback-test command or a generate-pattern command;
- and
- c) an interface unit coupled to said communication channel comprising a command-detector circuit, a loopback circuit, and a pattern-generator circuit;
- said command detector circuit responding to a loopback test command by activating said loopback circuit, said loopback circuit receiving said digital test signals transmitted by said test unit in said first direction and returning digital test signals to said test unit in said second direction, said returned test signals used by said test unit to determine if communication errors occur in either said first or said second direction;
- said command-detector circuit responding to said generate-pattern command by activating said pattern-generator circuit, said pattern-generator circuit generating a digital test data sequence for transmission in said second direction, said network test unit receiving said test data sequence and determining if transmission errors occurred in said second direction.
3 more elements
Dependencies are inferred from the claim text.