ITU T.50

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ITU-T recommendation T.50 specifies the International Reference Alphabet (IRA, formerly International Alphabet No. 5, IA5), a character set 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[edit]

At the beginning was the International Telegraph Alphabet No. 2#ITA2, a five bits code.

IA5 is an improvement based on seven bits bytes.

International Telegraph Alphabet No. 2#ITA2

  • 5 T.50 (09/1992) In force
  • 4 T.50 (11/1988) Superseded
  • 3 T.50 (10/1984) Superseded
  • 2 V.3 (11/1980) Superseded
  • 1 V.3 (10/1976) Superseded

Use[edit]

This standard is referenced by other standards such as RFC3966.[1]

It is also used by some Analog Modem such as Cisco ones.[2]

This standard is referenced by other standards such as RFC 3939 - Calling Line Identification for Voice Mail Messages.

Standardisation[edit]

  • Identical standard: ISO 646:1991 (Twinned)

References[edit]

External links[edit]