VT220 Programmer Reference Manual| Chapter 4 | Contents |
| Mnemonic | Code | Name | Action Taken |
|---|---|---|---|
| NUL | 0/0 | Null | Ignored when received. |
| ENQ | 0/5 | Enquiry | Answerback message is generated. |
| BEL | 0/7 | Bell | Generates bell tone if bell is enabled. |
| BS | 0/8 | Backspace | Moves cursor to the left one character position: if cursor is at left margin, no action occurs. |
| HT | 0/9 | Horizontal tabulation | Moves cursor to next tab stop, or to right margin if there are no more tab stops. Does not cause autowrap. |
| LF | 0/10 | Linefeed | Causes a linefeed or a new line operation, depending on the setting of new line mode. |
| VT | 0/11 | Vertical tabulation | Processed as LF. |
| FF | 0/12 | Form feed | Processed as LF. |
| CR | 0/13 | Carriage return | Moves cursor to left margin on current line. |
| SO (LS1) | 0/14 | Shift out (Lock shift G1) |
Invokes G1 character set into GL. G1 is designated by a select-character-set (SCS) sequence. |
| SI (LS0) | 0/15 | Shift in (Lock shift G0) |
Invoke G0 character set into GL. G0 is designated by a select-character-set sequence (SCS). |
| DC1 | 1/1 | Device Control 1 | Also referred to as XON. If XOFF support is enabled, DC1 clears DC3 (XOFF), causing the terminal to continue transmitting characters (keyboard unlocks) unless KAM mode is currently set. |
| DC3 | 1/3 | Device Control 3 | Also referred to as XOFF. If XOFF support is enabled, DC3 causes the terminal to stop transmitting characters until a DC1 control character is received. |
| CAN | 1/8 | Cancel | If received during an escape or control sequence, terminates and cancels the sequence. No error character is displayed. If received during a device control string, the DCS is terminated and no error character is displayed. |
| SUB | 1/10 | Substitute | If received during escape or control sequence, terminates and cancels the sequence. Causes a reverse question mark to be displayed. If received during a device control sequence, the DCS is terminated and reverse question mark is displayed. |
| ESC | 1/11 | Escape | Processed as escape sequence introducer. Terminates any escape, control or device control sequence which is in progress. |
| DEL | 7/15 | Delete | Ignored when received. Note: May not be used as a time fill character. |