16 Apr
2014
16 Apr
'14
10:13 a.m.
On 04/15/2014 04:44 PM, Paul Koning wrote:
I have the schematics for that. I should see about sending them to Al to
put on bitsavers.
Excellent. I
wasn't aware cyber1.org had a way to handle the 19/10 bit
frames. This gives me incentive. Since I need to build hardware in any
case to handle the keyboard and data to the display (as I said, I
received NO additional hardware) it should be simple enough to just do
some appropriate conversion to TCP/IP there as well and give it an
ethernet connection (l'll likely use a Beaglebone for the task. Kinda
overkill, but easy.) Should work well. The connection to cyber1 basically takes
the 19 bit word and splits it across 3 bytes of TCP data stream. So all you need to deal
with is clocking that out synchronously to the terminal. It?s actually 21 bits: a start
bit (!), 19 bits of data, parity. The start and parity bits aren?t in the TCP data
stream. Words of all zero serve as filler.
Beaglebone GPIO should have no trouble with this, I would think. If all else fails, a
shift register could be attached.
--
-Gary
On Apr 15, 2014, at 5:49 PM, Gary Oliver <go at
aerodesic.com> wrote:
Alas, no. I do, however, have the power supply manual for the unit and
it describes if gory detail the sequencing, ramps and limits for each of
the voltages. I don't have it in front of me, but I recall a severe
warning about when and how to bring up the 150 (or was it -150) volt
supply with respect to the logic and other control voltages.
Unfortunately, the power suppy et al were not part of the stuff I was
able to obtain. Fortunately, the manufacturer of the display (Corning
if I recall) graciously sent me, without charge, the four manuals for
the system components. This was WAY before my access to the intertubes,
so this was accomplished by dialing the old phone until I found a
sympathetic ear...
I suppose I should send the manuals to bitsavers.
-Gary
On 04/15/2014 02:16 PM, Paul Koning wrote:
> On Apr 15, 2014, at 4:50 PM, Gary Oliver <go at aerodesic.com> wrote:
>
>> I have the 'guts' to the earlier Plato terminal (the one with the
>> 512x512 plasma.) By 'guts', I mean the keyboard and display - no box or
>> electronics.
Do you have the plasma panel power supply? I hope so,
because that is a pile of esoteric magic that?s absolutely critical. The functioning of
the plasma panel depends critically on the waveform from the power supply. ...
Magnavox sounds familiar. Our terminal was
in a large sheet-metal box
without a micro I'm sure, given the time-frame (mid 1970s.) I looked at
the manuals on bitsavers, but they seem to refer to the video-terminal
variety. ....
2) Does this even make sense? Would one of these connected to the
"Plato Network" vie TCP/IP be able to do the stuff it could do native
(e.g. control the music synth, slide projector, etc.)
Yes, it could be connected.
The ASCII version is very easy to connect. The classic (19 bit) one would take a little
hardware to turn the TCP data stream into the correctly framed synchronous data to the
terminal (and to accept the 10 bit asynchronous terminal output for transmission over
TCP). So it could certainly work with the cyber1.org system.
Thanks for the info. I will research this project further.
Good luck. An
additional resource is Aaron Woolfson, who has restored a number of PLATO terminals and
knows them quite well. He?s very busy, but he said I could pass along his contact
information: woolfson at telswitch.com
paul