A data encoding scheme for transmission of data from one circuit to another circuit combines DBI encoding and non-DBI encoding and uses a data mask signal to indicate the type of encoding used. The data mask signal in a first state indicates that the data transmitted from one circuit to said another circuit is to be ignored, and the data mask signal in a second state indicates that the data transmitted from one circuit to said another circuit is not to be ignored. If the data mask signal is in the second state, a first subset of the data is encoded with data bus inversion and a second subset of the data is encoded differently from data bus inversion. Such encoding has the advantage that SSO noise is dramatically reduced when the encoded data is transmitted from one circuit to another circuit.