T.50 (standard) explained

ITU-T recommendation T.50 specifies the International Reference Alphabet (IRA), formerly International Alphabet No. 5 (IA5), a character encoding. ASCII is the U.S. variant of that character set.

The original version from November 1988 corresponds to ISO 646. The current version is from September 1992.

History

At the beginning was the International Telegraph Alphabet No. 2 (ITA2), 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• Recommendation V.3 IA5 (1968): Initial version, superseded
• Recommendation V.3 IA5 (1972): Superseded
• Recommendation V.3 IA5 (1976-10): Superseded
• Recommendation V.3 IA5 (1980-11): Superseded
• Recommendation T.50 IA5 (1984-10): Superseded
• Recommendation T.50 IA5 (1988-11-25): Superseded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^[1]

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.^[2]

Character set

The following table shows the IA5 character set. Each character is shown with the code point of its Unicode equivalent.

Standardisation

• Identical standard: ISO/IEC 646:1991 (Twinned)

See also

• ITU T.51

External links

• Official ITU-T T.50 page
• Tech Info - Character Codes (IA5 and ISO 646)

Notes and References

1. Web site: 7-bit character sets: Revisions of ASCII . Tuomas . Salste . Aivosto Oy . January 2016 . . 2016-06-13 . live . https://web.archive.org/web/20160613145224/http://www.aivosto.com/vbtips/charsets-7bit.html#body . 2016-06-13.
2. Web site: AT Command Set and Register Summary for NM-8AM-V2, NM-16AM-V2, WIC-1AM, and WIC-2AM Analog Modem WAN Interface Cards - 2: Syntax and Procedures [Cisco 3600 Series Multiservice Platforms] - Cisco Systems ]. Cisco.com . 2012-10-03 . dead . https://web.archive.org/web/20110907024347/http://www.cisco.com/en/US/docs/routers/access/modem/AT/wic/command/reference/atwic2.html . 2011-09-07 .