T.50 (standard)
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
[edit]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- Recommendation V.3 IA5 (1968): Initial version, superseded[1][2]
- Recommendation V.3 IA5 (1972): Superseded[1][2]
- Recommendation V.3 IA5 (1976-10): Superseded
- Recommendation V.3 IA5 (1980-11): Superseded
- Recommendation T.50 IA5 (1984-10): Superseded[2]
- Recommendation T.50 IA5 (1988-11-25): Superseded[1][2]
- Recommendation T.50 IRA (1992-09-18): In force[1][3]
Use
[edit]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.[4]
Character set
[edit]The following table shows the IA5 character set. Each character is shown with the code point of its Unicode equivalent.
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | |
| 0x | NUL | SOH | STX | ETX | EOT | ENQ | ACK | BEL | BS | HT | LF | VT | FF | CR | SO | SI |
| 1x | DLE | DC1 | DC2 | DC3 | DC4 | NAK | SYN | ETB | CAN | EM | SUB | ESC | FS | GS | RS | US |
| 2x | SP | ! | " | # | $ | % | & | ' | ( | ) | * | + | , | - | . | / |
| 3x | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | : | ; | < | = | > | ? |
| 4x | @ | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O |
| 5x | P | Q | R | S | T | U | V | W | X | Y | Z | [ | \ | ] | ^ | _ |
| 6x | ` | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o |
| 7x | p | q | r | s | t | u | v | w | x | y | z | { | | | } | ~ | DEL |
Undefined, showing instead the ASCII character at that location)
A character that, in some regions, can be combined with a previous character as a diacritic using the backspace character, which may affect glyph choice.
Standardisation
[edit]- Identical standard: ISO/IEC 646:1991 (Twinned)
See also
[edit]References
[edit]- ^ a b c d Salste, Tuomas (January 2016). "7-bit character sets: Revisions of ASCII". Aivosto Oy. urn:nbn:fi-fe201201011004. Archived from the original on 2016-06-13. Retrieved 2016-06-13.
- ^ a b c d International Alphabet No. 5 - Recommendation T.50, International Telecommunication Union (ITU) - The International Telegraph and Telephone Consultative Committee (CCITT) - Series T: Terminal Equipment and Protocols for Telematic Services, 1993-04-16 [1988-11-25], E 33116, archived from the original on 2017-03-19, retrieved 2017-03-18
- ^ International Reference Alphabet (IRA) - Information Technology - 7-bit Coded Character Set For Information Interchange - Recommendation T.50, International Telecommunication Union (ITU) - The International Telegraph and Telephone Consultative Committee (CCITT) - Terminal Equipment and Protocols for Telematic Services, 1993-04-16 [1992-09-18], E 3177, archived from the original on 2014-12-19, retrieved 2017-03-18
- ^ "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. Archived from the original on 2011-09-07. Retrieved 2012-10-03.