VT420 experiment needed

From: Michael Sokolov <msokolov_at_ivan.Harhan.ORG>
Date: Tue Feb 17 13:34:08 2004

I'm writing a software module that turns a DEC LK201 keyboard into an IFCTF
keyboard (one that generates ASCII/ISO codes and sequences) and among other
features supported on LK201 in various DEC products I want to implement hex
compose on the numeric keypad like on VT420. The problem is, some fine details
of how it should work are unclear and I don't have a VT420 to experiment on,
only VT320 and VT340 which don't have hex compose. I'm wondering if someone on
this list has a VT420 and could test something for me.

First, what happens if you press keypad Enter or keypad '.' in a compose
sequence? I can think of 3 reasonable ways the firmware can handle this:

* Do what it does for Tab, Return, arrow and functions keys in a compose
  sequence, i.e., cancel the compose sequence and let the pressed key do its
  normal non-compose action.
* Ignore the key (suppress the keyclick) and remain in the compose sequence in
  the same state.
* Store the invalid key in the compose sequence accumulator and proceed to the
  next character of the sequence. Then at the end of the compose sequence
  complain with a warning bell about the invalid sequence.

Can someone with a VT420 please try this and see which of the above (or
something else altogether) does the firmware do?

Also what happens if you mix a main keypad key and a numeric keypad key in a
compose sequence?

MS

P.S. Reverse-engineering state machines is fun, isn't it?
Received on Tue Feb 17 2004 - 13:34:08 GMT