1000BASE-T

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1000BASE-T or IEEE 802.3ab is a standard for gigabit ethernet over copper wiring. It requires, at a minimum, Category 5 cable. Category 5e ("Category 5 enhanced") and Category 6 cable may also be used. The 1000BASE-T standard was approved by the IEEE 802.3 in 1999.

In a departure from both 10BASE-T and 100BASE-TX, 1000BASE-T uses all four cable pairs for simultaneous transmission in both directions through the use of echo cancellation and a 5-level pulse amplitude modulation (PAM-5) technique. The symbol rate is identical to that of 100BASE-TX (125 Ms/s) and the noise immunity of the 5-level signaling is also identical to that of the 3-level signaling in 100BASE-Tx, since 1000BASE-T uses 4-Dimensional Trellis Coded Modulation (TCM) to achieve a 6 dB coding gain across the 4 pairs.

Furthermore, auto-negotiation is a requirement for using 1000BASE-T[1].

Each network segment can have a maximum distance of 100 metres. This usually consists of 90 m horizontal (inside the building), 9 m at the patch panel, and 1 m from the port to the computer or node.

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