Appendix A. Copper Test Failure Cause Tables

This appendix provides additional and more detailed lists of possible causes for certain cable test fault conditions to augment the short list presented in Chapter 10, “Troubleshooting Media.”


Wiremap failures are most often found at cable termination points, either at the RJ45 (plug or jack) or at an intermediate cross-connect or patch panel. They involve opens, shorts, and various pairing faults. Table A-1 provides a detailed listing of the most common sources of wiremap failures.

Table A-1. Common wiremap test failure fault sources



The “bad patch cord” message indicates excessive ...

Get Network Maintenance and Troubleshooting Guide: Field-Tested Solutions for Everyday Problems, Second Editon now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.