Within IEEE 802.3, the total number of symbols per second transferred to or from the medium dependent interface (MDI) on a single wire pair. For 100BASE-T4, the symbol rate is 25 MBd. For 100BASE-X, the symbol rate is 125 MBd. For 100BASE-T2, the symbol rate is 25 MBd. For 1000BASE-T, the symbol rate is 125 MBd