LANTEK User Manual - Ideal Industries
LANTEK User Manual - Ideal Industries
LANTEK User Manual - Ideal Industries
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Chapter 3<br />
Structured Cable Field Calibration and Testing<br />
Troubleshooting Impedance Problems<br />
Problem: High Impedance Readings<br />
Probable Causes<br />
Compression, stretching, or excessive bending damage to the<br />
cable.<br />
Defective connectors.<br />
Insulation damage at a connector.<br />
Ground loops created between cable shielding (if used) and<br />
equipment grounding (via RS-232 cable to computer, or auxiliary<br />
power).<br />
Improperly chosen cables or patch cords.<br />
Moisture in the cable.<br />
Other Tests Affected Test Possible Result<br />
Length<br />
Affected pairs will appear longer.<br />
Average Impedance Change in average impedance is inversely<br />
proportional to change in capacitance.<br />
Delay and Skew Test<br />
This test measures the period of time for a test signal applied to one end of a cable<br />
run to reach the other end. Skew indicates the difference between the measured time<br />
delay for that pair and the pair with the lowest value (displayed as 0.0 ns). Delay and<br />
Skew limits are set according to the currently selected cable type.<br />
Delay and Skew Errors<br />
Figure 3-19: Delay and Skew Test Screen<br />
Delay and skew measurements will usually differ slightly between pairs in the same<br />
cable. A substantial difference indicates a cable installation problem or a pair defect.<br />
Troubleshooting Delay and Skew Problems<br />
Problem: Excessive Differences between Measurements<br />
Probable Causes<br />
Other Tests Affected<br />
Cables which use different materials for insulating the four pairs of<br />
wires.<br />
A break or short in the pair.<br />
Excessive cable length.<br />
Cable installation problems.<br />
Not Applicable<br />
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