A data transmission system for a display device, which is an mBnB encoding system encoding a signal of m (m is a natural number) bits into a signal of n (n is a natural number and n>m) bits on the basis of a certain translation table to be transmitted thereafter, the system including: an output driver of outputting a gray scale voltage in accordance with the data decoded at a receiver side, in which in the translation table, a bit pattern with a larger data change index from among 2n pieces of bit patterns of the n bits of the data is assigned to a bit pattern with a larger amplitude of the gray scale voltage from among 2m pieces of bit patterns of the m bits of the data.