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The Installation of Cable LoadingWhen a cable is loaded, extensive "capacity unbalance" tests are made and the unbalances minimized.22 Figure 20 represents the end view of a cable "quad" or the four wires of a phantom group. Each wire has capacitance to each other wire and to ground (cable sheath), and these can be represented as shown. If each of the corresponding capacitances is the same, then no ca-pacitive unbalance exists, and no crosstalk will be produced from this source. That is, a conversation on the "white" pair W and WM (white and white mate) will not be heard on the "black" pair; neither will a conversation on the phantom B-BM and W-WM be transferred to either side circuit B and BM or W and WM. Cables are designed and manufactured to keep these unbalances small. When a cable is installed in service, adjacent lengths are spliced together so that the unbalances in one length tend to neutralize those in the next.22, 23
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Last Update: 2011-05-18