4 Oct
2000
4 Oct
'00
10:38 a.m.
From: Chuck McManis <cmcmanis(a)mcmanis.com>
Clearly the simplest solution is a 6PnT rotary switch,
some cables wired
up
with MMJ plugs crimped on their ends. I'm planning
to build one of these
as
I have all the parts and that will get the console
going on the
micro-cluster.
That would work if you assert RxD to spacing on disconnect.
Me, I cheat. I don't bother connecting a tube (unless required like
during initial install)
and when needed I use the VT1200 to connect via the net once that is up.
However, if you're willing to be really clever then
you can do much
better
than this. I've got a nice color terminal (the Link
MC70 although its
color
is a bit unstable these days :-() or I could use a DEC
VT340 (probably
the
actual version for display) and you could, with a bit
of smarts and some
buffering take output from the RS-423 lines, and prior to forwarding
them
on to the terminal you could inject ANSI color codes
on/off. This would
make the output from each console a different color. (keeping them
straight
is of course the challenge) If you are really clever
you don't allow one
console to interrupt another mid-line either. I've got an old single
board
Z80 system that could probably do this, or I could wimp
out and use a
CPLD
feeding a Scenix chip.
Could be done with Vt125 or better yet....
Like I used to do with a Vt320, the system write a status line (25th) in
response to a simple request "@who" which runs a DCL script. the
request was stored as the "respones line" on the terminal or as a
simple "w" [set W*ho="(a)who.com".com". Also other defined commands
terminate with a call to who. The status line also has current
directory
and account. the switch box was a LQPX2-SW and MMJ to DB/P25
cabling.
Allison