The Teletype Corp Inktronic was offered in Receive-Only (RO), and
Keyboard-Send-Receive (KSR) versions. The KSR is an ascii machine, while the RO
could be configured for ascii or baudot.
Shown above, is the Inktronic-KSR. Why is it so big?
Mike Mellinger (WA0SXV) related the following Inktronic tale:
"When I was working for the Washington University Computer Systems Lab (St.
Louis) in the era 1969-1974, one of my assignments was to update the
printing capabilities of our LINC's (Laboratory Instrument Computer) LAP
operating system. We first purchased a Model 38 and I got to introduce
upper/lower case printing to the machines. The LINC used a number of
special characters and the Model 38 has some characters we could use so that
we didn't need custom typewheels anymore.
Then someone, in a moment of weakness, decided to buy a nice fast Teletype
Inktronic printer. I was in favor of a real line printer but lost the
argument. Non-academic employees seldom win arguments in academic
The machine must have been the first ink-sprayer ever. That was obvious.
We shouldn't even talk about the documentation -- which was typical
Teletype. Of somewhat more value with the extensive circuit diagrams.
The machine used electrostatic charges to deflect the ink. This had a
number of interesting consequences.
First, the ink was special very liquid stuff that stained everything that it
came near. I still have a lab coat with Inktronic dots on it. If you got
near the machine, I think that the ink jumped out at you. Despite this, it
faded dreadfully and the few Inktronic printouts I have are faded nearly to
Second, in order to have more precise character formation, the ink had to be
maintained to an exact temperature. So the machine had a warm-up time.
Despite this, the characters were poorly formed and looked sprayed.
Somewhat more interesting is that because it had electronic character
formation and programmable ROM chips didn't really exist, Teletype invented
their own read-only memory. This was accomplished by having an array of
laminated cores representing the various dots in the characters. Then, for
each possible character there was a thin Mylar printed circuit on which a
single conductor was weaved through the appropriate cores to produce the
desired character format. The Mylar had holes punched in it so that Mylar
for all of the characters could be stacked on the core array. You pulsed
the appropriate character Mylar and the cores sensed the presence or absence
of a bit and printed accordingly. A bit bulky, a dreadful kluge, but kind
The problem was that we needed some special characters, but no one wanted to
even think about the cost of procuring the appropriate Mylar printed circuit
material and then etching and punching (the holes were square) it. After
much agonizing, I finally arrived at the solution of simply removing the 3
or 4 Mylar sheets representing the characters that we wanted to change and
then weaving, by hand, wire wrap wire around the cores and substituting each
of the wires for the appropriate sheet.
Of course, someone had purchased the machine with a parallel interface
instead of serial thus requiring not only device driver changes that would
have been necessary under any situation, but the engineering of a custom
parallel interface to the machine. All of that was pretty simple compared
to simply getting the beast to work and print the desired characters.
Believe it or not, it all eventually worked and we got a lot of use out of
the machine." [Mike Mellinger WA0SXV]