What is "control character"

n. (context computing English) A character which does not have a direct visual appearance as a glyph, but rather causes some other display action to occur, such as a transition to a new line.

n. ASCII characters to indicate carriage return or tab or backspace; typed by depressing a key and the control key at the same time [syn: ASCII control character]

In computing and telecommunication, a control character or non-printing character is a code point (a number) in a character set, that does not represent a written symbol. They are used as in-band signaling to cause effects other than the addition of a symbol to the text. All other characters are mainly printing, printable, or graphic characters, except perhaps for the "space" character (see ASCII printable characters).

All entries in the ASCII table below code 32 (technically the C0 control code set) are of this kind, including CR and LF used to separate lines of text. The code 127 ( DEL) is also a control character. Extended ASCII sets defined by ISO 8859 added the codes 128 through 159 as control characters, this was primarily done so that if the high bit was stripped it would not change a printing character to a C0 control code, but there have been some assignments here, in particular NEL. This second set is called the C1 set.

These 65 control codes were carried over to Unicode. Unicode added more characters that could be considered controls, but it makes a distinction between these "Formatting characters" (such as the Zero-width non-joiner), and the 65 Control characters.

The Extended Binary Coded Decimal Interchange Code (EBCDIC) character set contains 65 control codes, including all of the ASCII control codes as well as additional codes which are mostly used to control IBM peripherals.

0x00

0x10

0x00

NUL

DLE

0x01

SOH

DC1

0x02

STX

DC2

0x03

ETX

DC3

0x04

EOT

DC4

0x05

ENQ

NAK

0x06

ACK

SYN

0x07

BEL

ETB

0x08

BS

CAN

0x09

TAB

EM

0x0A

LF

SUB

0x0B

VT

ESC

0x0C

FF

FS

0x0D

CR

GS

0x0E

SO

RS

0x0F

SI

US

0x7F

DEL