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by arh68 660 days ago
> changes in the electric field travel at the speed of light

Isn't it ~2/3 c thru copper? Roughly equivalent to light-thru-glass. I'm not quite sure who is running hollow-core fiber.
2 comments
Jakob 659 days ago
TIL that signal speed in copper and in fiber is roughly similar, around 2/3 c. Thanks!
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thayne 658 days ago
It depends on the properties of the wire, such as the diameter, the purity of the copper, type of insulation, etc. In a twisted pair wire the length the light travels is also longer than the external lenghth of the wire.

Cat5 is has about the same velocity factor as fiber: 2/3, but Cat7 is closer to 3/4. Coaxial can get even higher.

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thayne 660 days ago
It depends on the properties of the wire, but it can be as high as over 0.99c.
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