22 Aug
2007
22 Aug
'07
4:49 p.m.
Tony Duell wrote:
I've just bought the base unit (VS240) for a VT240
terminal on E-bay
and
know little about it (OK, I know it's a DEC graphics terminal).
Perhaps somebody can enlightent me
There's a pocket service guide on Manx (along with a few owner's
manuals).
1) One site i looked at said a VT240 is a monochrome
unit, a VT241 is
the colour version. Is the only difference the monitor? Can I use a
colour
monitor with my base unit?
I believe I was told so by someone back at DEC. But I never got
close enough to one to be able to tell.
2) On the back are obvious connectors for an RS232 port (DB25),
current
loop (8 pin mate-n-lock). There's a DE9 labelled 'PR', presumably a
printer port, also RS232. A RJ11 keyboard socket, I assume an LK201
will
work here (yes?).
I _think_ all the VT2xx terminals shared common keyboards.
A BNC which seems ot be composite mono video. And a
DA15 plug, also for a monitor. I assume a VR201 links here, or a V241
with the right cable. Also, can I connect the keybaord to, say, the
back
of the VR201, or do I have to use the RJ11 on the terminal itself?
3) How much is known about the insides? Of course
I've taken it apart.
On this board, there's an 8085, 2681 (dual serial
chip), 8251 (USART,
maybe used for the keybaord interface), 7220 (graphics chip) -- along
with
what seemms to be much the same circuitry as a Rainbow colour card,
there
Sounds likely.
are a couple of PALs, I've not checked to see if
they're the same as
the
ones in the 'bow. Pletny of RAM and ROM, and some glue logic. And
another 40 pin chip, DC310. For some reason this is saying
'processor' to me. Is
it?
The DEC 1987 Semiconductor Databook just leaped off the shelf to
mention "DCT11" in my ear (Manx has a manual for the T11).
Antonio
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