Line/drop testing from a craft terminal using test unit

• US 5,361,293 A
• Filed: 04/16/1992
• Issued: 11/01/1994
• Est. Priority Date: 04/16/1992
• Status: Expired due to Term

• Current Assignee: Alcatel Network Systems India Limited (Nokia Corporation)
• Original Assignee: Alcatel Network Systems India Limited (Nokia Corporation)
• Inventors: Czerwiec, Richard M.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): LOOMIS, PAUL A
• Application Number:
  US07/869,618
• Time in Patent Office: 929 Days
• Field of Search: 379/6, 379/10, 379/24, 379/26, 379/30, 379/27, 379/29, 370/13, 370/16
• US Class Current: 379/27.02
• CPC Class Codes: H04M 1/24 Arrangements for testing
• CPC Class Codes: H04M 3/30 for subscriber's lines , for the local loop

Abstract

A subscriber equipment (210) is isolated (238, 234) at a line card (208) in a line shelf (200) and drop testing is conducted over a test-out bus (240) by a test unit (220) connected (236) to the subscriber equipment (210); the test unit (220) may be plugged into any line card slot in any of a plurality of line shelves (200, . . . , 202); if the test unit (220) is plugged into a line shelf (202) and it is desired to test subscriber equipment (210) in another line shelf (200), appropriate contacts (242 or 244) in test access units (246, 246a) in the corresponding line shelves (200, 202) are activated to provide access from the test unit in one (202) line shelf to the subscriber equipment connected into the other (200) line shelf; the test unit (220) may also be equipped with devices (211, 213) for conducting line testing over a cross-connect path created between the line under test and the test unit (220) wherein the line is terminated at the line shelf with terminations (TERMS) in the test access unit (246) to simulate the isolated subscriber equipment.

Claims

1. A method for testing in a digital loop carrier (DLC) system having a remote terminal (RT) connected between a plurality of subscribers and a central office or for testing in a fiber-in-the-loop system having a remote terminal (RT) connected between a central office and an optical network unit (ONU) by optical fibers and having metallic drop connections between a plurality of subscribers and the ONU, comprising the steps of:

selecting, from a craft interface in the RT or in the ONU, line and/or drop testing and a line number to be tested;

checking line status and, when busy, suspending testing but, when available, isolating a selected subscriber equipment from an associated line and, for

(i) line testing, by terminating the line with an impedance via a test-in bus and cross-connecting at the remote terminal the associated line and a test unit in a line card slot in the RT or the ONU and performing selected tests on the associated line and/or, for

(ii) drop testing, by connecting the selected subscriber equipment to the test unit via a test-out bus by providing selected test signals from the test unit to the subscriber equipment; and

providing test result signals via a craft interface at the ONU or the RT.

2. Apparatus, comprising:

control means, responsive to a request for testing signal from a craft interface, the request for testing signal being provided directly on a line unit interface bus (LUIB) or being one digital signal zero signal among a plurality of digital signal zero signals, for providing a line isolation control signal on the LUIB and for providing a cross-connect path between a line to be tested and the LUIB and responsive to line and drop test result signals for reporting to the craft interface;

isolation means, responsive to the line isolation control signal, for isolating a selected subscriber equipment from the line to be tested and having means, responsive to a line drop test initiation signal from the control means, for connecting a test-out bus to the equipment;

a test unit, connected by means of the cross-connect path via the LUIB to the line to be tested, for providing selected line tests and for providing the line test result signals to the control means via the LUIB; and

test access means, responsive to the line isolation control signal, for terminating the associated line with a selected impedance via a test-in bus and responsive to the line drop test initiation signal for providing line drop test sequence signals via the test-out bus to the selected subscriber equipment and for receiving test response signals back from the equipment for comparison with expected response signal values for providing the drop test result signals to the control means via the LUIB.

3. A test unit, comprising:

a card for insertion in a line card slot of a line card shelf in a structure having a number of associated line card shelves, wherein the shelf recognizes the card as a test unit and provides a selected test configuration for the structure via a line unit interface bus in the shelf;

means on the card, responsive to a drop test request from the line unit interface buss in the shelf, for providing a drop test sequence on an output thereof via a test-out bus in the line card shelf;

means on the card, responsive to a line test request from the line unit interface bus, for providing a selected line test sequence on the line unit interface bus and wherein the card provides report signals for reporting results of the line and drop test sequences via the line unit interface bus to a craft interface in the structure.

4. The test unit of claim 3, wherein the test unit output is connected to the test-out bus with pins inserted into card receptacles in a line shelf for receiving pins on line cards having the same orientation as the pins on the test unit card.

5. The test unit of claim 4, wherein the test unit is insertable into any line card slot of any line shelf in the structure for testing any line card in said any line shelf via test access units connected between associated line card shelves.