|
The Vietnamese Standard Code for Information Interchange (VISCII) is a character set comprising the Vietnamese alphabet, punctuation, and other graphemes. Vietnamese requires slightly too many (134) letter/diacritic combinations to make a traditional extended ASCII character set for it. There are essentially 3 possible solutions to this. #Use a variable width encoding #Use combining diacritical marks, as Windows-1258 does #Replace something from ASCII VISCII went for the last option, replacing 6 of the least problematic (e.g., least likely to be recognised by an application and acted on specially) C0 control codes (STX, ENQ, ACK, DC4, EM, and RS) with 6 of the least used uppercase letter/diacritic combinations. While this may cause issues with some programs in handling VISCII text if they use those control codes, it creates fewer complications than either of the other two solutions. However, it leaves absolutely no space available for things other than accented letters such as symbols, superscripted numbers, curved quotes, proper dashes, etc. VISCII was designed by the Vietnamese Standardization Working Group ((Viet-Std Group )) based in the Silicon Valley in California in 1992 while they were working with the Unicode consortium to include precomposed Vietnamese characters in the Unicode standard. It was fully supported by the (TriChlor Software Group ) in California, which released a lot of software packages, libraries, and fonts for MS-DOS and Windows, Unix, and Macintosh. However, it, along with other Vietnamese-specific character sets, fell out of usage with the adoption of Unicode. VISCII-compliant software is still available at many ( ftp sites ). ==Code page layout== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Vietnamese Standard Code for Information Interchange」の詳細全文を読む スポンサード リンク
|