100BASE-T Ethernet signalling, also known as Fast Ethernet, represents a type of Ethernet networking technology. This term refers to the transmission of data at a rate of 100 megabits per second (Mbps) over twisted pair cabling. The "100" in 100BASE-T denotes the speed of data transfer, which is 100 Mbps. The "BASE" indicates baseband transmission, meaning only Ethernet signals are carried on the cable. The "T" signifies twisted pair cabling, which is the type of cable used for data transmission. There are several variations of 100BASE-T Ethernet, including 100BASE-TX, 100BASE-T4, and 100BASE-FX. The 100BASE-TX uses two pairs of high-quality twisted-pair cables, while the 100BASE-T4 uses four pairs of regular-quality twisted-pair cables. The 100BASE-FX uses fibre optic cables. In 100BASE-T Ethernet, data transmission occurs through the use of physical layer signalling techniques. This involves converting the data into a signal that can be transmitted over the network cable. The signalling technique used in 100BASE-T Ethernet is 4B/5B, which converts 4-bit data into 5-bit symbols for transmission. This helps to maintain a balanced number of ones and zeros in the data stream, reducing the potential for error in data transmission.