1. A method of transmitting an electronic voucher through a short message, the method which comprises: converting an electronic voucher to be transmitted into a bit stream; mapping each n-bits of the bit stream to any one text character of one of a plurality of text character groups, wherein text characters in each of the text character groups have at least one same or similar geometry or image feature, and a bit number n corresponding to each text character depends on a number m of the text character groups; arranging the text characters obtained by the mapping into a character sequence; and transmitting the character sequence through a short message; wherein, the plurality of text character groups are achieved by dividing a text character set in terms of the geometry or image features of the text characters of the text character set; and a criterion of dividing the text character set in terms of the geometry or image features of the text characters of the text character set includes: axial symmetry and rotational symmetry of the text characters.
1. A method of transmitting an electronic voucher through a short message, the method which comprises: converting an electronic voucher to be transmitted into a bit stream; mapping each n-bits of the bit stream to any one text character of one of a plurality of text character groups, wherein text characters in each of the text character groups have at least one same or similar geometry or image feature, and a bit number n corresponding to each text character depends on a number m of the text character groups; arranging the text characters obtained by the mapping into a character sequence; and transmitting the character sequence through a short message; wherein, the plurality of text character groups are achieved by dividing a text character set in terms of the geometry or image features of the text characters of the text character set; and a criterion of dividing the text character set in terms of the geometry or image features of the text characters of the text character set includes: axial symmetry and rotational symmetry of the text characters. 5. The method according to claim 1 , wherein the text character groups are formed by grouping GB2312 codes, ASCII codes, numerals and English alphabets or full-width English alphabets in terms of their geometry or image features.