ISO 2047

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ISO 2047 (Information processing – Graphical representations for the control characters of the 7-bit coded character set) is a standard for graphical representation of the control characters for debugging purposes, such as may be found in the character generator of a computer terminal; it also establishes a two-letter abbreviation of each control character.[1] It started out as ANSI X3.32-1973 (American National Standard – Graphic Representation of the Control Characters of American National Standard Code for Information Interchange in 1973[2] and became an ISO standard in 1975.[1] In addition, RFC 1345 "Character Mnemonics & Character Sets" is cited as the ISO 2047 two-letter abbreviation of the control character. ISO 2047, ECMA-17[3] in Europe, GB/T 3911-1983 in China, that corresponds to KS X 1010[4] in Korea (formerly KS C 5713) has been established as a standard. It was enacted "graphical representation of information exchange capabilities for character" JIS X 0209:1976 (former JIS C 6227) in Japan, and was abolished on January 20, 2010.

While the ISO/IEC 646 three-letter abbreviation (such as "ESC"), or caret notation (such as "^[") are still in use, the graphical symbols of ISO 2047 are considered outdated and rare.[5]

Character table[edit]

Name Symbol[1][3][6][7][8] 2-letter
00 NUL Null U+2395 NU
01 TC1, SOH Start of Heading U+2308 SH
02 TC2, STX Start of Text U+22A5 SX
03 TC3, ETX End of Text U+230B EX
04 TC4, EOT End of Transmission U+2301[9] ET
05 TC5, ENQ Enquiry [10] U+22A0 EQ
06 TC6, ACK Acknowledge U+2713 AK
07 BEL Bell U+237E[9] BL
08 FE0, BS Backspace [11] BS
09 FE1, HT Horizontal Tabulation U+2AAB HT
0A FE2, LF Line Feed U+2261 LF
0B FE3, VT Vertical Tabulation U+2A5B VT
0C FE4, FF Form Feed U+21A1 FF
0D FE5, CR Carriage Return U+2AAA CR
0E SO Shift Out U+2297 SO
0F SI Shift In U+2299 SI
10 TC7, DLE Data Link Escape U+229F DL
11 DC1, XON, CON[12] Device Control 1 U+25F7 D1
12 DC2, RPT,[12] TAPE[13] Device Control 2 U+25F6 D2
13 DC3, XOF, XOFF Device Control 3 U+25F5 D3
14 DC4, COF, KMC,[12] TAPE[13] Device Control 4 U+25F4 D4
15 TC8, NAK Negative Acknowledge U+237B[9] NK
16 TC9, SYN Synchronization U+238D SY
17 TC10, ETB End of Transmission Block U+22A3 EB
18 CAN Cancel U+29D6 CN
19 EM End of Medium U+237F[9] EM
1A SUB Substitute Character U+2426[14] SB
1B ESC Escape U+2296 EC
1C IS4, FS File Separator U+25F0 FS
1D IS3, GS Group Separator U+25F1 GS
1E IS2, RS Record Separator U+25F2 RS
1F IS1 US Unit Separator U+25F3 US
20 SP Space U+25B3 SP
7F DEL Delete [15] DT


  1. ^ a b c "ISO 2047:1975 Information processing – Graphical representations for the control characters of the 7-bit coded character set". ISO. ISO. Retrieved 13 April 2020.
  2. ^ American National Standard – Graphic Representation of the Control Characters of American National Standard Code for Information Interchange, American National Standards Institute, 3 July 1973
  3. ^ a b ECMA-17, Graphic Representation of the Control Characters of the ECMA 7-Bit Coded Character Set for Information Interchange (withdrawn)
  4. ^ KS X 1010-2007 Graphical representations control characters for Information interchange
  5. ^ Agim Çami, Control characters in ASCII and Unicode, Agim Çami – Computer Architecture web site, 1 July 2019
  6. ^ Michael P. Frank, A Proposed Set of Mnemonic Symbolic Glyphs for the Visual Representation of C0 Controls and Other Nonprintable ASCII Characters, 14 September 2006 (mirror)
  7. ^ Information Representation, 28 August 2016 – This is the site cited by Michael P. Frank
  8. ^ Information Technology - Irish 7-bit coded character sets, 13 December 1995 – Note that in this article the glyphs for ENQ, BS, CR and SO are anomalous, possibly to accommodate the low resolution.
  9. ^ a b c d Specifically cited in The Unicode Standard, Version 6.2. Miscellaneous Technical. Range: 2300–23FF.
  10. ^ In ISO 2047, ✠ is the primary glyph and ⊠ is only a fallback, but ECMA-17 lists only ⊠.
  11. ^ As a best-fit approximation ↖ could be used. Other defensible choices could be ⤺, ↰, ⮢, ⮪, ⮌ or ⮏.
  12. ^ a b c Primary Control Set of Data Syntax II of CCITT Rec. T.101, Comité Consultatif International Télégraphique et Téléphonique, 31 July 1987
    International Interworking for Videotex Services » forpost » T101 » t101PDFe » t101p1.pdf, Terminals for Telematic Services, International Telecommunication Union, 11 November 1994
  13. ^ a b On the Teletype Model 33 TAPE and TAPE would control the tape punch, whereas XON and XOFF would control the reader. ENQ was labelled WRU for 'who are you?'
    Robert McConnell, James Haynes & Richard Warren, Understanding ASCII Codes, NADCOMM Papers and Writings, December 2002
  14. ^ Specifically cited in The Unicode Standard, Version 6.2. Control Pictures. Range: 2400–243F.
  15. ^ As a best-fit approximation ▨, 🮙 or ␥ could be used.

External links[edit]