Method and system for testing XDSL wiring

• US 20030179858A1
• Filed: 03/14/2002
• Published: 09/25/2003
• Est. Priority Date: 03/14/2002
• Status: Active Grant

• Current Assignee: Netgear Holdings Ltd. (NETGEAR, Inc.), NETGEAR, Inc.
• Original Assignee: Westell Technologies Incorporated
• Inventors: Bella, Greg, Noll, Bill
• Granted Patent: US 7,076,030 B2
• Time in Patent Office: Days
• US Class Current: 379/1.03
• CPC Class Codes: H04M 1/24 Arrangements for testing
• CPC Class Codes: H04M 1/7385 Programmable or microprocessor-controlled
• CPC Class Codes: H04M 3/2209 for lines also used for data transmission
• CPC Class Codes: H04M 3/30 for subscriber's lines , for the local loop
• CPC Class Codes: H04M 3/301 Circuit arrangements at the subscriber's side of the line

Abstract

In an XDSL system, a network interface device can connect between a central office and a customer premises. The network interface device can monitor for an indication to enter a test mode. In the test mode, the network interface device can provide a test signal to the central office, which can be used to test central office equipment and transmission lines connecting the network interface device with the central office. The network interface device can also provide the test signal to the customer premises, and the test signal can be used to test customer premises wiring and equipment.

Claims

1. A network interface device for use in an XDSL transmission system, the network interface device comprising:

a test detector for detecting an indication to enter a test mode, the test detector having first and second test detector terminals, wherein the first test detector terminal connects to a first voltage node, and the second test detector terminal connects to a second voltage node;

a test circuit for providing a test signal to the XDSL transmission system during the test mode, the test circuit having first and second test circuit terminals, wherein the first test circuit terminal selectively connects to the first voltage node via a first connector, and wherein the second test circuit terminal selectively connects to the second voltage node via a second connector;

a third voltage node selectively connectable to the first voltage node, wherein the third voltage node connects to the first voltage node when the first test circuit terminal is disconnected from the first voltage node, and wherein the third voltage node is disconnected from the first voltage node when the first test circuit terminal connects to the first voltage node;

a fourth voltage node selectively connectable to the second voltage node, wherein the fourth voltage node connects to the second voltage node when the second test circuit terminal is disconnected from the second voltage node, and wherein the fourth voltage node is disconnected from the second voltage node when the second test circuit terminal connects to the second voltage node;

a first resistor connected across the first voltage node and the third voltage node; and

a second resistor connected across the second voltage node and the fourth voltage node.

2. The network interface device of claim 1, wherein the first voltage and second voltage nodes interface with a first twisted pair transmission line connected to a central office, and wherein the third and fourth voltage nodes interface with a second twisted pair transmission line connected to a customer premises.

3. The network interface device of claim 1, wherein the test circuit comprises:

a tone generator for generating the test signal during the test mode; and

a line power circuit for drawing current from an XDSL transmission line connected to a central office, using the current to power the tone generator.

4. The network interface device of claim 1, wherein the first resistor and the second resistor each have a resistance of about 1000 ohms.

5. The network interface device of claim 1, wherein the first and second connectors are a double pole double throw relay.

6. The network interface device of claim 1, wherein the test detector is operably connected to the first connector.

7. The network interface device of claim 1, wherein the test circuit is operably connected to the first connector.

8. The network interface device of claim 1, wherein the XDSL transmission system is an ADSL transmission system.

9. A network interface device for testing transmission lines in an XDSL transmission system, the network interface device comprising:

a test detector for detecting an indication to enter a test mode, the test detector having first and second test detector terminals, wherein the first test detector terminal connects to a first voltage node, and wherein the second test detector terminal connects to a second voltage node;

a line power circuit for drawing current from a transmission line in the XDSL transmission system in order to produce power, the line power circuit having first and second line power circuit terminals, wherein the first line power circuit terminal selectively connects to the first voltage node via a first connector, and wherein the second line power circuit terminal connects to the second voltage node via a second connector;

a tone generating circuit for providing a test signal to the XDSL transmission system during the test mode, the tone generating circuit having first and second tone generating circuit terminals, wherein the first tone generating circuit terminal connects to a third line power circuit terminal, wherein the second tone generating circuit terminal connects to a fourth line power circuit terminal, and wherein the tone generating circuit receives power from the line power circuit;

a third voltage node selectively connectable to the first voltage node, wherein the first relay connects the third voltage node to the first voltage node when the first line power circuit terminal is disconnected from the first voltage node, and wherein the first relay disconnects the third voltage node from the first voltage node when the first line power circuit terminal is connected to the first voltage node;

a fourth voltage node selectively connectable to the second voltage node, wherein the second relay connects the fourth voltage node to the second voltage node when the second line power circuit terminal is disconnected from the second voltage node, and wherein the second relay disconnects the fourth voltage node from the second voltage node when the second line power circuit terminal is connected to the second voltage node;

a first resistor in series with a third line power circuit terminal and the first connector, wherein the first connector selectively connects the first resistor to the third voltage node; and

a second resistor in series with a fourth line power circuit terminal and the second connector, wherein the second connector selectively connects the second resistor to the forth voltage node.

10. The network interface device of claim 9, wherein the first and second voltage nodes interface with a first twisted pair transmission line connected to a central office, and wherein the third and fourth voltage nodes with a second twisted pair transmission line connected to a customer premises.

11. The network interface device of claim 9, wherein the test detector can selectively engage the first and second connectors, and wherein the line power circuit can selectively disengage the first and second connectors.

12. The network interface device of claim 9, wherein the first resistor and the second resistor each have a resistance of about 1000 ohms.

13. The network interface device of claim 9, wherein the first and second connectors are each double throw double pole relays.

14. The network interface device of claim 9, wherein the test detector is operably connected to the first connector.

15. The network interface device of claim 9, wherein the tone generating circuit is operably connected to the first connector.

16. The network interface device of claim 9, wherein the XDSL transmission system is an ADSL transmission system.

17. The network interface device of claim 9, wherein the line power circuit is operably connected to the tone generating circuit through a transformer.

18. A method for testing an XDSL transmission system, the method comprising:

receiving an indication;

responsively sending a test signal over an XDSL transmission line connected to a central office, wherein the test signal is sent for a predetermined amount of time;

selectively engaging an impedance; and

sending the test signal over an XDSL transmission line connected to a customer premises, wherein the test signal is sent through the impedance, and wherein the test signal is sent for the predetermined amount of time.

19. The method of claim 18, further comprising:

selectively disengaging the impedance after the predetermined amount of time.

20. The method of claim 18, wherein receiving an indication comprises:

receiving an indication from the central office.

21. The method of claim 18, wherein receiving an indication comprises:

receiving an indication from an ADSL modem located on the customer premises.

22. The method of claim 18, wherein the indication is a battery short.

23. The method of claim 18, wherein the test signal is a predetermined sequence of tones from 25 KHz to 1 MHz.

24. A method for testing XDSL wiring in a customer premises, the method comprising:

receiving a test signal from a test generation circuit through a selectively engagable impedance, wherein the test signal is sent for a predetermined amount of time;

detecting at least one tone in the test signal;

measuring an amplitude of the at least one tone; and

comparing the amplitude of the at least one tone with an expected value.

25. The method of claim 24, further comprising:

sending the test generation circuit an indication to send the test signal.

26. The method of claim 24, further comprising:

selectively disengaging the impedance after the predetermined amount of time.

27. The method of claim 24, further comprising:

displaying a user interface;

receiving through the user interface an indication to enter a test mode; and

sending the test generation circuit an indication to send the test signal.

28. The method of claim 24, wherein detecting at least one tone comprises:

detecting a predetermined sequence of tones; and

measuring an amplitude of each tone in the predetermined sequence of tones.

29. The method of claim 28, wherein detecting a sequence of tones comprises:

detecting a sequence of tones in the range of 170 KHz to 1 MHz.

30. The method of claim 24, wherein the expected amplitude is about negative 26 dBm.

31. The method of claim 24, wherein the XDSL wiring is ADSL wiring.