Plato terminal

From: Gary Oliver <go_at_ao.com>
Date: Sat Jan 30 00:21:49 1999

I'm working from memory, but I believe the original Plato terminals
used a non-standard "character" length that was something like
20 bits for receive and 12 bits for transmit. And they were
possibly strange rates as well. The "receive character" actually
could contain several characters in one "packet". If your's is one
of the original, you may find it somewhat problematic to talk to it
in a meaningful way <g>

My experience with these stems from a short-lived attempt back in
about 1974 - I was working on a "second generation" terminal mux
for our home-grown timesharing system at Oregon State, and the
computer center had (if I recall) three of the Plato terminals
(which were normally used via modem to the system in Urbana, IL).
The "powers that be" decided they wanted to connect them to the
local t.s. system and it became "my job" to find out how. It was
not an easy fit and we gave up after a few months of trying to
coax the mux into producing and receiving with the right framing
characteristics. But I did have to learn (but quickly forgot)
the weirdness of the communication protocol.

By the way, a while back I obtained a plasma display unit from an
old Plato terminal (512x512 neon plasma display with "see through"
rear-projection screen. I also found the Owens-Illinois technical
manuals for this unit and was wondering if it is the same display
as in the original Plato terminals. If so, I could make copies
for you.

The manuals I have are:

UM607 - DigiVue User Manual 512-60 Display D141
MM608 - DigiVue Maintenance Manual 512-60 Display D141
UM609 - DigiVue User Manual 512-60 Power Pack S159 / S205
MM610 - DigiVue Maintenance Manual 512-60 Power Pack S159 / S205

Someday I need to make a controller and fire mine up so I can
play with it. Takes all sorts of power supplies (I have just the
display - not the power pack) but the interface is pretty simple.
It uses a 30 pin data connection whose inputs are X,Y position,
write/erase/sync and some other misc control and status lines.

They were really cool displays for their time.

Gary

At 09:46 PM 1/29/99 -0600, you wrote:
>Well, i figured it was about time I took my terminal out of the closet and
>tried to get it to work again. Well, the good news is it still appears
>to be working.
>
>This beast is a Control Data Corporation Plato terminal. As far as I know,
>its the original model of plato terminal. Touch screen, vector graphics,
>square monitor area... big base unit a tad bigger than my IBM pentium
>computer, with a video display unit that sits on top and merges with
>teh base unit. Keyboard is about as non-standard as i've ever seen.
>
>There are side panels on both sides of the base unit, which contain all
>the circuit cards for the smart terminal. It looks like this was made
>around 1975 since the proms are dated then, and some other board had a chip
>dated 1974... 8080a cpu.. I have the optional modem card, not that i can
>use it (1200 rcv, 150 xmt ;) ;)
>
>This baby can support all sorts of baud rates, most of which are useless ;)
>Lets see, if i recieve at 1260 baud, i can transmit at one of these rates:
>1260, 630, 157.5, 126, 78.2 baud.
>
>If I recieve at 1200 baud (yes! a useful rate) I can transmit at 1200, 600,
>150, 120, 75 baud.
>
>I only have 4K ram, does anyone have a spare 4k ram board for this ;) ;)
>
>I can see why I havent been using this, it looks like I need to wire up
>a rs-232 adapter box. Pin 3 is recieve, pin 14 is transmit, pin 7 is ground.
>Am I correct in assuming that i just need to move 14 to 2, or am i getting
>2 and 3 swapped around? I woudl want to connectthis termianl to a cp/m
>computer as its console, and not to a modem.
>
>Ok, time for the impossible question: Does anyone have a manual for this?
>
>I had some leftover old 1000 speed film in teh old automatic-everything
>el-cheapo 35mm camera, so i turned onteh flash and snapped a few photos,
>so with any luck i'll have some poor images of this beast by tomorrow.
>
>Hmm, if no manual is available, maybe an old termcap entry might make
>this terminal useful again....
>
>How many thousands of dollars is this beast worth? i may go broke buying
>cloth covers for this stuff ;)
>
>-Lawrence LeMay
Received on Sat Jan 30 1999 - 00:21:49 GMT