Protocols Interoperability and Usage
Computer applications dealing with plain text only need to concern themselves with the six format effectors (0x08 through 0x0D) in the default C0 set. Only HT, LF, and CR are universally well handled, as BS is often used by applications to indicate deleting the previous character, and VT and FF are often poorly handled by applications that do not assume the use of a fixed character and page size. On the other hand, the C1 control character NEL intended as a single byte substitute for the common two-byte sequence CR LF is often accepted by plain text applications. Very few applications interpret the other C0 and C1 control codes, as they are not needed for plain text.
The ESC code is used extensively to introduce commands to control printing and display devices, for instance in the ANSI escape codes, and PCL, the printer language from Hewlett-Packard printers and compatibles.
NUL has the meaning of "end of string" in C programming language and derivatives such as C++. This meaning is usually not intended in a text stream, but the result is that NUL often cannot be assigned any other meaning.
In addition, some transmission protocols such as ANPA-1312 do make extensive use of control characters SOH, STX, ETX and EOT. Other well known but now nearly obsolete ones are BEL, ACK, NAK and SYN.
The official English language names of some control codes were revised in the most recent edition of the standard for control codes in general (ISO 6429:1992 or ECMA-48:1991) to be neutral with respect to the graphic characters used with them, and to not assume that, as in the Latin script, lines are written on a page from top to bottom and that characters are written on a line from left to right. The abbreviations used were not changed, as the standard had already specified that those would remain unchanged when the standard is translated to other languages. Where the name has been changed, the original name from which the abbreviation was derived is also given in in the tables below.
Read more about this topic: C0 And C1 Control Codes
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