23 Aug
2010
23 Aug
'10
3:49 p.m.
On 8/23/10, John Ball <ball.of.john at gmail.com> wrote:
So I picked up both a MicroVAX 2000 with 120mb MFM
drive and MMJ terminal
adapter and a VAXstation 2000 with 40mb ST-251, keyboard, mouse, and some
little breakout box for the latter two.
Those machines are identical underneath - the only difference is the
installed framebuffer (or not) and a jumper (in one position for a
MicroVAX 2000, the other position for a VAXstation 2000), in case you
didn't already know.
Both systems power up and the drives don't make
any nasty noises...
Good. In case your ST-251 dies, it's just an ST-251, and the boot
ROMs can format a blank one.
but in both cases I have no way to communicate with
them. The MicroVAX I
can't talk to simply because I lack an MMJ cable
That can be solved, I'm sure. I know a common solution back in the
day was a 6-wire cable with an MMJ on one end and either an RJ45 or
RJ11 on the other end, depending on which modular connector standard
you were using at your site (we had Nevada Western 6-pin gear at our
place). The other solution was to not use the adapter box and plug a
DE9 console cable (same as a MicroVAX II, IIRC) into J3. You won't
have easy access to the other two serial ports (though you could make
a level shifter yourself), but it should be easy enough to make a
console cable with stuff many of us on the list have lying around the
house (don't know how well fixed you are for making random cables)
but the more interesting
VAXstation with it's 4-bit framebuffer simply because I don't see how on
earth you connect up a monitor to it.
As Ian pointed out, J5. You'll need a specific cable to go with your
framebuffer and monitor. There are a couple of options - mono vs RGB,
IIRC.
The keyboard and mouse break out box
connect to the monitor port but the box itself has no connections for a
monitor to be plugged in.
That's because the "break out box" as you are calling it, is a
MicroVAX 2000-specific option to do voltage shifting of the mouse and
keyboard serial channels as well as integrate the console connector
into an "easy to access" format.
The three ways I know to connect to a uV/VS2K are:
1. set the jumper for VAXstation, and plug a BC18 or BC19 monitor
cable on J5 and plug in a DEC mouse, DEC keyboard and compatible tube.
2. set the jumper for MicroVAX and plug a DEC console cable (BCC08)
into J3 and use some flavor of dumb terminal or terminal emulator for
a console.
3. set the jumper for MicroVAX and plug an MMJ into the console port
on the adapter box and proceed like #2 above.
How did this work and what types of monitor were
compatible? I might have
access to a VR201 if I want to pay shipping from MA to western canada.
You want something like a VR260 or VR290. The VR201 is RS-170
("NTSC") mono video, which is almost certainly too low a bandwidth to
handle the output of a workstation. The VR201 will work great with a
Rainbow or a VT240 base or a DECmate, but not a VAXstation.
There might well be plenty of workstation tubes out there that work
just as well as a DEC one, but unless they have BNC inputs for color
and sync, you might have to roll your own cable.
In addition to Ian's link, you might find this document to be helpful:
http://decdoc.itsx.net/pdp11nl/v2000sg1.pdf
-ethan