The Terminal configuration panel allows you to control the behaviour of PuTTY's terminal emulation.
Auto wrap mode controls what happens when text printed in a PuTTY window reaches the right-hand edge of the window.
With auto wrap mode on, if a long line of text reaches the right-hand edge, it will wrap over on to the next line so you can still see all the text. With auto wrap mode off, the cursor will stay at the right-hand edge of the screen, and all the characters in the line will be printed on top of each other.
If you are running a full-screen application and you occasionally find the screen scrolling up when it looks as if it shouldn't, you could try turning this option off.
Auto wrap mode can be turned on and off by control sequences sent by the server. This configuration option only controls the default state. If you modify this option in mid-session using Change Settings, you will need to reset the terminal before the change takes effect.
DEC Origin Mode is a minor option which controls how PuTTY interprets cursor-position control sequences sent by the server.
The server can send a control sequence that restricts the scrolling region of the display. For example, in an editor, the server might reserve a line at the top of the screen and a line at the bottom, and might send a control sequence that causes scrolling operations to affect only the remaining lines.
With DEC Origin Mode on, cursor coordinates are counted from the top of the scrolling region. With it turned off, cursor coordinates are counted from the top of the whole screen regardless of the scrolling region.
It is unlikely you would need to change this option, but if you find a full-screen application is displaying pieces of text in what looks like the wrong part of the screen, you could try turning DEC Origin Mode on to see whether that helps.
DEC Origin Mode can be turned on and off by control sequences sent by the server. This configuration option only controls the default state. If you modify this option in mid-session using Change Settings, you will need to reset the terminal before the change takes effect.
Most servers send two control characters, CR and LF, to start a new line of the screen. The CR character makes the cursor return to the left-hand side of the screen. The LF character makes the cursor move one line down (and might make the screen scroll).
Some servers only send LF, and expect the terminal to move the cursor over to the left automatically. If you come across a server that does this, you will see a stepped effect on the screen, like this:
First line of text
Second line
Third line
If this happens to you, try enabling the "Implicit CR in every LF" option, and things might go back to normal:
First line of text Second line Third line
Not all terminals agree on what colour to turn the screen when the server sends a "clear screen" sequence. Some terminals believe the screen should always be cleared to the default background colour. Others believe the screen should be cleared to whatever the server has selected as a background colour.
There exist applications that expect both kinds of behaviour. Therefore, PuTTY can be configured to do either.
With this option disabled, screen clearing is always done in the default background colour. With this option enabled, it is done in the current background colour.
The server can ask PuTTY to display text that blinks on and off. This is very distracting, so PuTTY allows you to turn blinking text off completely.
With local echo disabled, characters you type into the PuTTY window are not echoed in the window by PuTTY. They are simply sent to the server. (The server might choose to echo them back to you; this can't be controlled from the PuTTY control panel.)
Some types of session need local echo, and many do not. In its default mode, PuTTY will automatically attempt to deduce whether or not local echo is appropriate for the session you are working in. If you find it has made the wrong decision, you can use this configuration option to override its choice: you can force local echo to be turned on, or force it to be turned off, instead of relying on the automatic detection.
Normally, every character you type into the PuTTY window is sent immediately to the server the moment you type it.
If you enable local line editing, this changes. PuTTY will let you edit a whole line at a time locally, and the line will only be sent to the server when you press Return. If you make a mistake, you can use the Backspace key to correct it before you press Return, and the server will never see the mistake.
Since it is hard to edit a line locally without being able to see it, local line editing is mostly used in conjunction with local echo (section 3.3.6). This makes it ideal for use in raw mode or when connecting to MUDs or talkers. (Although some more advanced MUDs do occasionally turn local line editing on and turn local echo off, in order to accept a password from the user.)
Some types of session need local line editing, and many do not. In its default mode, PuTTY will automatically attempt to deduce whether or not local line editing is appropriate for the session you are working in. If you find it has made the wrong decision, you can use this configuration option to override its choice: you can force local line editing to be turned on, or force it to be turned off, instead of relying on the automatic detection.