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The VT52 was a very popular video terminal by DEC, introduced 1975. The CRT displays 24 lines of 80 characters in both upper and lower case.

VT52 terminal

It uses a custom processor built from TTL parts to execute 1024 words of 8-bit wide microcode. The data path is 7 bits wide, as is the 2048-word RAM. The predecessor VT50 is almost identical, except there is only 512 words of microcode, 1024 words of RAM, the CRT display 12 lines, and text is upper case only.

A VT52-compatible terminal emulator was used in the Atari TOS operating system.

Escape sequences

Due to its popularity, the VT52 escape sequences became a de facto standard for microcomputers for a while, before VT100 and ANSI took over.

Name Sequence Description
Line Feed LF Move cursor down. On last line, scroll text up.
Cursor Down ESC B Move cursor down. On last line, do not scroll.
Reverse Line Feed ESC I Move cursor up. On first line, scroll text down.
Cursor Up ESC A Move cursor up. On first line, do not scroll.
Cursor Right ESC C Move cursor right. On last column, stay there.
Cursor Left ESC D, or BS Move cursor left. On first column, stay there.
Home ESC H Move cursor to top line, first column.
Carriage Return CR More cursor to first column.
TAB Move cursor to next tab stop.
Direct Cursor Addressing ESC Y <line> <column> Move cursor.
Erase to End of Line ESC K Erase from cursor position to end of line.
Erase to End of of Screen ESC J Erase from cursor position to end of screen.
Ring the Bell BEL Sound the buzzer
Identify Terminal Type ESC Z Respond e.g. "ESC K" for a plain VT52.
Enter Hold Screen Mode ESC [
Exit Hold Screen Mode ESC \
Enter Alternate Keypad Mode ESC =
Exit Alternate Keypad Mode ESC >
Enter Graphics Mode ESC F
Exit Graphics Mode ESC G
Extensions from Digital Research
Erase and Home ESC E Erase screen and move cursor to top line, first column.
Erase Current Line ESC l
Erase to Beginning of Line ESC o
Erase to Beginning of Screen ESC d
Insert Line ESC L
Save Cursor Position ESC j
Restore Cursor Position ESC k
Reverse Video ESC p
Normal Video ESC q
Set Foreground Color ESC b <color>
Set Background Color ESC c <color>
Enable Cursor ESC e
Disable Cursor ESC d
Enable Line Wrap ESC v
Disable Line Wrap ESC w

External links