4.4.1 Changing the action of the Backspace key

Some terminals believe that the Backspace key should send the same thing to the server as Control-H (ASCII code 8). Other terminals believe that the Backspace key should send ASCII code 127 (usually known as Control-?) so that it can be distinguished from Control-H. This option allows you to choose which code PuTTY generates when you press Backspace.

If you are connecting over SSH, PuTTY by default tells the server the value of this option (see section 4.24.2), so you may find that the Backspace key does the right thing either way. Similarly, if you are connecting to a Unix system, you will probably find that the Unix stty command lets you configure which the server expects to see, so again you might not need to change which one PuTTY generates. On other systems, the server's expectation might be fixed and you might have no choice but to configure PuTTY.

If you do have the choice, we recommend configuring PuTTY to generate Control-? and configuring the server to expect it, because that allows applications such as emacs to use Control-H for help.

(Typing Shift-Backspace will cause PuTTY to send whichever code isn't configured here as the default.)