power over ethernet and 1000 base-T

Answered Question
Dec 17th, 2008
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hi every body!

Poe uses unused pair in 100 base-T.But In 1000base-T, all four pairs are used for data.Since there is no unused pair in 1000base-T , then how is the power transmitted ?

thanks a lot!


Correct Answer by Giuseppe Larosa about 8 years 5 months ago

Hello Sarah,

PoE is supported also on 1000 baseT the key is that the power is a DC signal while the ethernet signal is variable over time ( = use higher frequencies so they can be splitted)


However, a GE capable IP phone is more hungry of power this has led to rapid consumption of power supplies in our more modern campus


if it takes 12W instead of 7W for example it makes quite a difference


Hope to help

Giuseppe


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Correct Answer
Giuseppe Larosa Wed, 12/17/2008 - 12:49
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Hello Sarah,

PoE is supported also on 1000 baseT the key is that the power is a DC signal while the ethernet signal is variable over time ( = use higher frequencies so they can be splitted)


However, a GE capable IP phone is more hungry of power this has led to rapid consumption of power supplies in our more modern campus


if it takes 12W instead of 7W for example it makes quite a difference


Hope to help

Giuseppe


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