US5559427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Instrument and method for testing local area network cables
Assignee: Fluke Corp
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Filing: 1994-04-04
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Granted: 1996-09-24
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Expires: 2014-04-04
Abstract
Abstract An instrument and method for the troubleshooting and verification of copper-wire local area network (LAN) cable systems provides a series of resistance and capacitance measurements between all possible wire pairs using a pair of switch matrices and a software method for evaluating the measurements which are stored in a two-dimensional matrix. The stored measurements are evaluated against predetermined figures of merit and the decision pattern in matrix form is compared to that of a known good LAN cable system. Error messages responsive to mismatches are generated and presented to the operator via a user interface. Near-end cross talk (NEXT) isolation is evaluated using a mathematically calculated differential capacitance technique. Error messages are generated responsive to difference capacitance values larger than a figure of merit correlated to an acceptable level of NEXT isolation.
Inventors
- 👤 Mark E. Hinds
- 👤 Robert J. Lewandowski
- 👤 Thomas P. Locke
- 👤 Tzafrir Sheffer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:05
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/08; H; H04; H04L; H04L43/00; H04L43/50; G01R31/50; G01R31/58
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
182 words
A LAN cable test instrument for testing a LAN cable having a near-end and a far-end, comprising: (a) input means for coupling to a plurality of wires from said LAN cable at said near-end, said plurality of wires forming twisted-wire pairs within said LAN cable; (b) first and second switch means coupled to said input means, said first switch means selectively coupling a first wire of said plurality of wires to a first output and said second switch means selectively coupling a second wire of said plurality of wires to a second output; (c) measurement means with a first input coupled to said first output and a second input coupled to said second output, said measurement means measuring the resistance and the capacitance between said first and second wires to produce resistance and capacitance measurement values; (d) memory means coupled to said measurement means for storing said resistance and capacitance measurement values; and (e) a microprocessor coupled to said said memory means wherein said microprocessor operates on said resistance and capacitance measurement values to determine said twisted-wire pairs in said LAN cable.
Claim 2
Dependent Claim
182 words
A LAN cable test instrument for testing a LAN cable having a near-end and a far-end, comprising: (a) input means for coupling to a plurality of wires from said LAN cable at said near-end, said plurality of wires forming twisted-wire pairs within said LAN cable; (b) first and second switch means coupled to said input means, said first switch means selectively coupling a first wire of said plurality of wires to a first output and said second switch means selectively coupling a second wire of said plurality of wires to a second output; (c) measurement means with a first input coupled to said first output and a second input coupled to said second output, said measurement means measuring the resistance and the capacitance between said first and second wires to produce resistance and capacitance measurement values; (d) memory means coupled to said measurement means for storing said resistance and capacitance measurement values; and (e) a microprocessor coupled to said said memory means wherein said microprocessor operates on said resistance and capacitance measurement values to determine said twisted-wire pairs in said LAN cable.
Claim 3
Dependent Claim
35 words
A LAN cable test instrument according to claim 1 wherein said memory means contains said resistance and capacitance measurement values for each pair of said plurality of wires formed by said first and second wires.
Claim 4
Dependent Claim
37 words
A LAN cable test instrument according to claim 2 wherein said microprocessor calculates a difference capacitance matrix from said capacitance measurement values in said memory means to evaluate near-end cross-talk isolation between each of said twisted-wire pairs.
Claim 5
Dependent Claim
35 words
A LAN cable test instrument according to claim 1 wherein said microprocessor compares said resistance and capacitance measurement values against a first predetermined value to detect a short circuit between said first and second wires.
Claim 6
Dependent Claim
35 words
A LAN cable test instrument according to claim 1 wherein said microprocessor compares said resistance and capacitance measurement values against a second predetermined value to detect an open circuit between said first and second wires.
Claim 7
Dependent Claim
26 words
A LAN cable test instrument according to claim 1 further comprising a display coupled to said microprocessor for displaying said twisted-wire pairs of said LAN cable.
Claim 8
Dependent Claim
46 words
A LAN cable test instrument according to claim 1 further comprising a cable identifier having an identifier number, said cable identifier coupled to said far-end of said LAN cable to provide a predetermined resistance value associated with said identifier number across said first and second wires.
Claim 9
Dependent Claim
29 words
A LAN cable test instrument according to claim 7 wherein said microprocessor compares said predetermined resistance value against a series of figures of merit to determine said identifier number.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-09-24 | 2000-03-25 | 2000-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-09-24 | 2004-03-25 | 2004-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-09-24 | 2008-03-25 | 2008-09-24 | $7700.00 | Window Closed / Lapsed |