ITU-T
The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...
recommendation T.50 specifies the International Reference Alphabet (IRA), formerly International Alphabet No. 5 (IA5), a
character encoding
Character encoding is the process of assigning numbers to graphical character (computing), characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical v ...
.
ASCII
ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...
is the U.S. variant of that character set.
The original version from November 1988 corresponds to
ISO 646
ISO/IEC 646 ''Information technology — ISO 7-bit coded character set for information interchange'', is an International Organization for Standardization, ISO/International Electrotechnical Commission, IEC standard in the ...
. The current version is from September 1992.
History
At the beginning was the
International Telegraph Alphabet No. 2
The Baudot code () is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use before ASCII. Each ch ...
(
ITA2
The Baudot code () is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use before ASCII. Each Chara ...
), a five-bit code. IA5 is an improvement, based on seven-bit bytes.
* Recommendation V.3 IA5 (1968): Initial version, superseded
* Recommendation V.3 IA5 (1972): Superseded
* Recommendation V.3 IA5 (1976-10): Superseded
* Recommendation V.3 IA5 (1980-11): Superseded
* Recommendation T.50 IA5 (1984-10): Superseded
* Recommendation T.50 IA5 (1988-11-25): Superseded
* Recommendation T.50 IRA (1992-09-18): In force
Use
This standard is referenced by other standards such as RFC 3939 ("Calling Line Identification for Voice Mail Messages"). It is also used by some
analog modems such as Cisco ones.
Character set
The following table shows the IA5 character set. Each character is shown with the code point of its
Unicode
Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...
equivalent.
Standardisation
* Identical standard: ISO/IEC 646:1991 (Twinned)
See also
*
ITU T.51
References
{{reflist
External links
Official ITU-T T.50 page
Character encoding
Character sets
ITU-T recommendations
ITU-T T Series Recommendations