EDIT Bell (Ctrl-G) Ring the Bell
Originally, this ASCII Code control character told the receive terminal to sound a warning signal - a function similar to the bell signal of a typewriter at the end of a line. Some PCs until today upon receiving the ASCII message \"0007\" make a warning sound.

English synonyms: bell, bel, beep, audible sign

Typography
Purportedly, there are some fonts which have got a bell icon (also printable) at this position.

_ _ _ _ _ _
A control character serves to initiate certain operations in printers or PCs without, however, encoding any visible typographic character (glyph).

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EDIT History On teletype equipment, this control code caused a single ding of a metal bell much like those used on rotary telephones.

The audible sign is already included in the so-called Murray Code which was made a standard in 1932 as the International Telegraph Alphabet #2 (CCITT-2 or ITA2). In 1963, it was included in the ASCII Code which today is a Unicode subset.

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EDIT Modern Usage Modern terminal equipment, many command line interfaces, and even some printers generate a beep through whatever sound device is available (often a built in speaker).

In Graphical User Interfaces, Ctrl-G is generally a shortcut for the goto editing action.

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EDIT Linux When a BEL is received, play the standard system beep sound.

Sound generation
The function of BEL is by no means technically obsolete (even though audible signals today are often programmed in a different way). Provided the internal speaker is not switched off or has been redirected to a functional I/O-port, compilation of the following primitive programme

#include<stdio.h>
main() {putchar(\\\'\\\\a\\\');}

ensures sounding of a signal tone on any standard Linux processor.
\\\'\\\\a\\\' represents the C notation of the character discussed in this article and may generically be replaced by \\\'\\\\007\\\'

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