[GreenKeys] Model 29 ASR

Wed Aug 17 17:18:59 EDT 2016

Teletype would make machines with odd codes for customers.  Going way back
to the Burroughs 220 (vacuum tube computer) there was a Model 28 RO
console printer that had the type box scrambled for some Burroughs code.

I know Univac used some M35 typing units for console printers on their
computers, with their own keyboards, but I don't know offhand what code
they were arranged for.

Since Spectra 70 was a System/360 clone it probably used some subset of
EBCDIC in the Model 35.  Model 35 could print only 64 characters of
whatever code, so it was probably upper case only.

One of my friends discovered some Model 29 RO printers at a surplus
store in Oakland, and was told they were part of some RCA computer
(pre Spectra 70).  He bought some of them and got parts from Teletype
to convert them to Model 35 and sold them to some dealer in Los Angeles.
And when I worked for G.E. there were some Model 29 printers there,
which a young man was hired to convert to Model 35.  So those escaped
from the Bell System.

On Wed, 17 Aug 2016, 73131.3073 at compuserve.com wrote:

> Years ago I had a Model 35 KSR that was the control console for an RCA
> Spectra 70 computer system. It was painted in the white and baby blue colors
> of that system and had the big round RCA logo on it. It was definitely NOT
> at ASCII machine but rather BCD or EBCDIC, I don't know which.
> 
> Tim Swarthout, WA5QEG
> 
> 
> 
> -----Original Message-----
> From: Jim Haynes <jhhaynes at earthlink.net>
> To: ralph irish <w8roi at wowway.com>
> Cc: greenkeys <greenkeys at mailman.qth.net>
> Sent: Wed, Aug 17, 2016 10:51 am
> Subject: Re: [GreenKeys] Model 29 ASR
> 
> When I was living in the Chicago area I got a couple of machines by way
> of Michigan Bell, but I don't remember how it was arranged. Probably
> Bert Prall had something to do with it.
> 
> One of these, which I still have, was the Delta Airlines version of the
> 28ASR which I have written about several times in the past. The other
> I don't remember if I got the whole ASR or just the cabinet, but it was
> one of the "pink" cabinets like Model 29s were made in. I converted
> that to an 8-level machine using Model 35 parts. I never did like the
> Model 35 cabinet anyway, and this one I just repainted dark brown and
> put the M35 stuff inside. (As they say of certain artists, this is when
> I was in my Dark Brown phase.)
> 
> The Model 29 as we know it was not EBCDIC; it was 6-level IBM BCD code,
> a forerunner of EBCDIC to be sure, but only 6-level and upper case only.
> As you have no doubt read it was originally developed as a 6-level
> up/low case machine to replace the Model 20 in Teletypesetter service,
> but apprently nobody wanted to buy any. (Marketing goof on Teletype's
> part, I guess. By then hot metal typesetting and Teletypesetter were
> on the way out.) So it was reworked a little with the IBM BCD code for
> internal Bell System use in data processing. It was officially called
> the Model 28 Integrated Data Processing set. Bell didn't want any of them
> to escape into the world at large. One reason I'm told is that it would
> seem they were playing favorites with IBM and ignoring the other computer
> companies which had slightly different versions of the BCD code. That
> reason seems bogus, because it would be trivial to modify it for some
> other BCD code. The more substantial reason was that development of
> ASCII was under way and Bell didn't want anything that would compete with
> ASCII to get out there; they wanted to insure that ASCII would be the one
> standard. In the meantime the military had Fieldata and I believe that
> was what got used in AUTODIN, though no Fieldata teleprinters were
> released - AUTODIN came with an electronic box that could convert Baudot
> or BCD to its own transmission code.
> 
> EBCDIC was a late-comer in the code development. During the development
> of ASCII, IBM kept putting up objections that were unacceptable to the
> other companies participating in the standard development. The main point
> of contention is that Hollerith punched-card code has some gaps in the
> alphabet, with other characters in the gaps. BCD does also because it
> is really just a simple translation from Hollerith. And IBM considered
> this so important that they wanted to require any new standard code to
> retain the property. In this they were wrong, since 512 bytes of memory
> would provide conversion tables between any two 8-level codes and there
> is no real need for a conversion that can be done by trivially simple
> logic. But IBM has always had a penchant for solving the problems of
> the previous generation of equipment, like they say the generals are
> always fighting the previous war. The good guys insisted there should be
> no breaks in the alphabet, so that sorting would not be upset by the
> funny characters in the middle. So ASCII had to have an unbroken series
> of binary numbers representing A through Z.
> 
> IBM surprised everyone by suddenly withdrawing their objections to ASCII,
> and the standard was adopted. Then IBM announced their new System/360
> computer line and EBCDIC. EBCDIC has the breaks in the alphabet that
> they wanted. I assume IBM thought they could use their dominant marketing
> position to establish EBCDIC as a de facto standard and that ASCII would
> then wither away, with only some legacy services such as TWX using it.
> Since the U.S. government required ASCII in all its computer systems
> thenceforth, IBM put an ASCII mode bit into System/360, which made some
> very minor change to the way the system operated, and which was so
> unimportant that it was dropped from System/370.
> 
> I believe what turned the tide in favor of ASCII was the Model 33. Not
> in its intended role as a TWX terminal, but in the totally new role of
> a computer remote terminal and minicomputer console device. The
> minicomputer and time-sharing businesses had no need for punched card
> input; and there was nothing to compete with the Model 33 in DataPhone
> service as a remote terminal, nor hardwired to the computer as a local
> console. What we now call the mainframe computer companies really had
> no means of attaching cheap start-stop terminals to their systems; they
> preferred schemes in which a single terminal adapter polled multiple
> terminals on the same line for messages.
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