itty-bitty-vtty for the Apple IIgs Updated

Kelvin Sherlock has released the fifth release of his itty-bitty-vtty vt-100 emulator for the Apple IIgs. The program emulates the vt100 with a modem port running at 9600 baud and 8N1 which are the same as the MAME emulator defaults.

Changes in Release 5

  • fix issues identified by vttest. aside from things that can’t be supported, it’s pretty good now.
  • control-space generates a control code (0x00)
  • command-Q to quit
  • command-L to toggle local/online mode
  • control panel only available in ROM 3 now (since ROM1 lacks the _RemoveCDA tool call)
  • Control panel shows more parameters (including outbound data)
  • backspace now send 0x7f rather than 0x08. 0x08 can still be achieved via control-H or option-delete or the extended keyboard delete key (VT100 keyboard have a backspace and a delete key. most of the time they’re equivalent but emacs treats control-h as the help key)
  • option-return sends line feed (0x0a).
  • command 1-4 sends PF1-PF4 (clear, =, /, * on the keypad)
  • auto-repeat (DECARM) support.


The documentation for itty-bitty-vtty are available from the vt100 User Guide website at:

Program Downloads

The latest version of itty-bitty-vtty program disk for the Apple IIgs and the source code for the program are available for free download from the itty-bitty-vtty Github page at:

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