MBits Ethernet

Signals sent over all 10 Mbit/s media systems uses Manchester encoding. Manchester encoding combines data and clock into bit symbols, which provide a clock transition in the middle of each bit. 
A logical zero (0) is defined as a signal that is high for the first half of the bit period and low for the second half, i.e. a negative signal transition. A logical (1) is defined as a positive signal transition in the middle of the bit period. The signal transition makes it easy for a receiver to synchronise with the incoming signal and to extract data from it. A drawback is that the worst case signalling rate is
twice the data rate.A link test signal is transmitted when there is no data to send.