VT220 Programmer Reference Manual| Chapter 4 | Contents |
| Difference Area | Level 1 (VT100 Mode) |
Level 2 (VT200 Mode) |
|---|---|---|
| Keyboard | Sends ASCII only. Keystrokes that normally send DEC Supplemental Characters transfer nothing. (Interpreted as an error.) User-defined keys are do not operate. Special function keys and six editing keys do not operate (except F11, F12, and F13, which send ESC, BS, and LF, respectively). |
Permits full use of VT220 keyboard. |
| 7 or 8 bits | The 8th bit of all received characters is set to zero (0). | The 8th bit of all received characters is significant. |
| Character Sets | Only ASCII, national replacement characters, and DEC special graphics are available. | All VT220 character sets are available. |
| C1 Control Characters | All transmitted C1 controls are forced to S7C1 state and sent as 7-bit escape sequences. | – |