For some reason, this feature only works properly when Num Lock is on. We don't know why. 4.4.7 Enabling a DEC-like Compose key DEC terminals have a Compose key, which provides an easy-to-remember way of typing accented characters. You press Compose and then type two more characters. The two characters are ‘combined’ to produce an accented character. The choices of character are designed to be easy to remember; for example, composing ‘e’ and ‘`’ produces the ‘è’ character. If your keyboard has a Windows Application key, it acts as a Compose key in PuTTY. Alternatively, if you enable the ‘AltGr acts as Compose key’ option, the AltGr key will become a Compose key. 4.4.8 ‘Control-Alt is different from AltGr’ Some old keyboards do not have an AltGr key, which can make it difficult to type some characters. PuTTY can be configured to treat the key combination Ctrl + Left Alt the same way as the AltGr key.
By default, this checkbox is checked, and the key combination Ctrl + Left Alt does something completely different. PuTTY's usual handling of the left Alt key is to prefix the Escape (Control-[) character to whatever character sequence the rest of the keypress would generate. For example, Alt-A generates Escape followed by a. So Alt-Ctrl-A would generate Escape, followed by Control-A.
If you uncheck this box, Ctrl-Alt will become a synonym for AltGr, so you can use it to type extra graphic characters if your keyboard has any.
(However, Ctrl-Alt will never act as a Compose key, regardless of the setting of ‘AltGr acts as Compose key’ described in section
4.4.7
.) 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. 4.5.1 ‘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. •‘Make default system alert 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.
•‘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. •‘Beep using the PC speaker’ is self-explanatory. •‘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’. 4.5.2 ‘Taskbar/caption indication on bell’ This feature controls what happens to the PuTTY window's entry in the Windows Taskbar if a bell occurs while the window does not have the input focus.