PuTTY and the Bell panel

The Bell panel controls the terminal bell feature: the server's ability to cause PuTTY to beep at you.

In the default configuration, when the server sends the character with ASCII code 7 (Control-G), PuTTY will play the Windows Default Beep sound. This is not always what you want the terminal bell feature to do; the Bell panel allows you to configure alternative actions.

Set the style of bell

This control allows you to select various different actions to occur on a terminal bell:

Selecting "None" disables the bell completely. In this mode, the server can send as many Control-G characters as it likes and nothing at all will happen.

"Play Windows Default Sound" is the default setting. It causes the Windows "Default Beep" sound to be played. To change what this sound is, or to test it if nothing seems to be happening, use the Sound configurer in the Windows Control Panel.

"Play a custom sound file" allows you to specify a particular sound file to be used by PuTTY alone, or even by a particular individual PuTTY session. This allows you to distinguish your PuTTY beeps from any other beeps on the system. If you select this option, you will also need to enter the name of your sound file in the edit control "Custom sound file to play as a bell".

"Visual bell" is a silent alternative to a beeping computer. In this mode, when the server sends a Control-G, the whole PuTTY window will flash white for a fraction of a second.

Taken from: http://the.earth.li/~sgtatham/putty/0.52/htmldoc/Chapter4.html#4.5