DATA TRANSMISSION METHOD AND A DATA TRANSMISSION DEVICE

A data transmission method for transmitting a data signal using four data signal levels during a unit interval and transmitting a data bus inversion (DBI) signal using two DBI signal levels during the unit interval, the method including: receiving n (n is a natural number) data, each of the n data including a first bit and a second bit; counting the number of data in which the first bit and the second bit have the same value among the n data; in response to the counting result being less than or equal to a predetermined number, transmitting the n data using the four data signal levels, together with a DBI signal having a first DBI signal level; and in response to the counting result being greater than the predetermined number, transmitting data, which is obtained by changing a value of either of the first bit and the second bit of the n data, using the four data signal levels, together with a DBI signal having a second DBI signal level different from the first DBI signal level.