Cancel character

In telecommunications and character encoding, the term cancel character refers to a control character which may be either of:

1. "CAN", "Cancel", U+0018, or ^X used to indicate that the data with which it is associated are in error or are to be disregarded. Exact meaning can depend on protocol. For example:
   • In some journalistic text transmission formats, it signifies that the preceding word should be deleted; it is sometimes called "Kill Word" ("KW") in this context.^[1]
   • In some Videotex formats, it stops any running macros.^[2][3] In others, it clears the current line after the cursor position (compare EL).^[4]
2. "CCH", "Cancel Character", U+0094, or ESC T used to erase the previous character. This character was created as an unambiguous alternative to the much more common backspace character ("BS", U+0008), which has a now mostly obsolete alternative function of causing the following character to be superimposed on the preceding one.

References

1. International Press Telecommunications Council (1976-03-25). Control set for newspaper text transmission (PDF). ITSCJ/IPSJ. ISO-IR-26.
2. CCITT (1987-07-31). Primary Control Set of Data Syntax I of CCITT Rec. T.101 (PDF). ITSCJ/IPSJ. ISO-IR-132.
3. CCITT (1987-07-31). Primary Control Set of Data Syntax III of CCITT Rec. T.101 (PDF). ITSCJ/IPSJ. ISO-IR-135.
4. CCITT (1987-07-31). Primary Control Set of Data Syntax II of CCITT Rec. T.101 (PDF). ITSCJ/IPSJ. ISO-IR-134.

•  This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22.