<P> ASCII is one of the IEEE milestones . </P> <P> ASCII was developed from telegraph code . Its first commercial use was as a seven - bit teleprinter code promoted by Bell data services . Work on the ASCII standard began on October 6, 1960, with the first meeting of the American Standards Association's (ASA) (now the American National Standards Institute or ANSI) X3. 2 subcommittee . The first edition of the standard was published in 1963, underwent a major revision during 1967, and experienced its most recent update during 1986 . Compared to earlier telegraph codes, the proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists, and added features for devices other than teleprinters . </P> <P> Originally based on the English alphabet, ASCII encodes 128 specified characters into seven - bit integers as shown by the ASCII chart above . Ninety - five of the encoded characters are printable: these include the digits 0 to 9, lowercase letters a to z, uppercase letters A to Z, and punctuation symbols . In addition, the original ASCII specification included 33 non-printing control codes which originated with Teletype machines; most of these are now obsolete . </P> <P> For example, lowercase i would be represented in the ASCII encoding by binary 1101001 = hexadecimal 69 (i is the ninth letter) = decimal 105 . </P>

How many characters are specified in ascii scheme