Bell character is an ASCII control character, code 7 (^G). When it is sent to a printer or a terminal, nothing is printed, but an audible signal is emitted instead. Terminal emulators usually offer visual bell which flashes the terminal window briefly to show the user where the alert occurred.

A bell code also exists in Baudot code, which has been used in teleprinters in some form since 1874. Sending a bell code would get the attention of the teleprinter operator at the other end of the line.

In the C programming language, the bell character is represented as 'a' ("alert" or "audible"). In Unicode, there is a character for visual representation of bell character, ”symbol for bell“, U+2407 (␇) — not to be confused with the actual bell character, U+0007.

In the Windows Command prompt, as with the earlier PC-DOS or MS-DOS command prompts on which it is based, and in the command prompt on Unix-like systems, the user can type the word "echo" followed by a CTRL+G, which will appear as

echo ^G

and when the user presses enter, the computer will emit a beep sound.

The beep can be disabled, if required on most machines, either through a registry or configuration file change, or through an application such as Microsoft PowerToys.