This paper proposes the revised Roman character code system using Unicode 3.0. The background of the paper is whether the Latin character code system th using in the world in Unicode V.3 is proper or not in the side of the transmission efficiency in data communications. In data communications, when the consecutive 4 bits or 8 bits of "0" bit from the information devices input into the line coder, its consecutive "0" bits are scrambled to the predetermined bit patterns to avoid the syncronization loss. The paper was based on the statistical data for the using frequency of the alphabet letter and the proposed rule for characters coding in [1]. The paper was focused to improve of Unicode itself and UTF-8 code system. As a result of the paper, when the proposed coding systems for Latin character in Unicode 3.0 itself and UTF-8 code system, the scrambler efficiency using HDB-3 in the line coder of the data transmission system could be improved about 3645 ~ 31400% and 480 ~ 1700% respectively.