[Info-vax] AlphaVM-free emulator with all additional peripheral components

[Johnny Billquist]

On 2012-08-02 19:41, Bob Koehler wrote:
> In article <jve1ul$brn$1 at Iltempo.Update.UU.SE>, Johnny Billquist <bqt at softjar.se> writes:
>
>> I might as well give the answer. It's the DECLL escape sequence, which
>> is used to control some lights on the keyboard.
>
>     I have a test program which runs throught the LEDs on VT100.  I've
>     run it on VT200, 300, and 400, a couple of hardware VT clones, and
>     several software VT emulators.
>
>     I don't recall a light on VT200 responding, but all those which were
>     not VT100 accepted and ignored the sequences without error.

You don't get "errors" for unknown escape sequences. Escape sequences 
can't give errors. If it's unknown/undefined, it's just a case of 
"nothing happens".

>     So I just figured the lights were "virtual".

:-)

Anyway, the VT500 (at least 520/525) do have lights that can be 
controlled. Same as the VT100.

	Johnny