- 2069 Asar · 2 marks
Why wires are twisted in twisted pair
Short answer
Twisting ensures both wires receive nearly equal electromagnetic interference, which cancels out at the differential receiver. It also reduces crosstalk between pairs, and more twists per meter improve performance.
Why do we twist two wires in twisted pair cable?
Two parallel wires act as an antenna. Each picks up external electromagnetic interference and also radiates, causing crosstalk with neighbouring pairs.
When the two wires are twisted, each wire is alternately closer to the noise source and then farther from it. Both wires therefore pick up almost the same amount of noise. The receiver uses the difference of the two wire voltages (a differential receiver), so this equal noise cancels out. The twisting also reduces crosstalk between adjacent pairs, and more twists per metre give better performance (higher category cables).
✓ Answer checked by Claude Sonnet 5.5
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