In a departure from both 10BASE-T and 100BASE-TX, 1000BASE-T uses four lanes over all four cable pairs for simultaneous transmission in both directions through the use of echo cancellation with adaptive equalization called hybrid circuits (this is like telephone hybrid) and five-level pulse-amplitude modulation (PAM-5). The symbol rate is identical to that of 100BASE-TX (125 megabaud (MBd)) and the noise immunity of the five-level signaling is also identical to that of the three-level signaling in 100BASE-TX, since 1000BASE-T uses four-dimensional trellis coded modulation (TCM) to achieve a 6 dB coding gain across the four pairs.
in a departure from both 10base-t and 100base-tx 1000base-t uses four lanes over all four cable pairs for simultaneous transmission in both directions through the use of echo cancellation with adaptive equalization called hybrid circuits (this is like telephone hybrid) and five-level pulse-amplitude modulation (pam-5) the symbol rate is identical to that of 100base-tx (125 megabaud (mbd)) and the noise immunity of the five-level signaling is also identical to that of the three-level signaling in 100base-tx since 1000base-t uses four-dimensional trellis coded modulation (tcm) to achieve a 6 db coding gain across the four pairs