Difference between Manchester and differential Manchester encoding?

Answer 1

Manchester encoding transmits different waveforms to distinguish between 0 and 1. For example, 1 is represented by a high voltage for the first half of the bit, followed by a low voltage (or a negative voltage) in the last half. A 0 should be the exact opposite: low voltage in the first half and high voltage in the second half.

Wikipedia explains the principle of differential Manchester encoding better than I could:

A '1' bit is indicated by making the first half of the signal equal to the last half of the previous bit's signal i.e. no transition at the start of the bit-time. A '0' bit is indicated by making the first half of the signal opposite to the last half of the previous bit's signal i.e. a zero bit is indicated by a transition at the beginning of the bit-time. In the middle of the bit-time there is always a transition, whether from high to low, or low to high. A reversed scheme is possible, and no advantage is given by using either scheme.