[GreenKeys] Some more info on Teletype model numbers

[jhaynes@alumni.uark.edu]

I talked with Walt Zenner 20 August 2003

Numbered models are pretty much a Bell System thing.  Some model numbers
were assigned to machines that were never produced.

Model 10 - Western Electric machine, by Pfannenstiehl et al  Typebar page
   printer with stationary platen
Model 11 - Morkrum, typewheel page printer based on Blickensderfer
   typewriter (according to Slayton; Zenner says not based on Blick typewriter)
Model 12 - well-known machine, Morkrum, typebar page printer with moving
   platen
Model 13 - Model 10 retrofitted with Morkrum Model 12 typing unit
Model 14 - well-known Morkrum machine  It seems, according to the catalog,
   that the GPE perforator and XD transmitter-distributor were also 
   considered part of the Model 14 line.
Model 15 - well-known Teletype machine
Model 16 - a stock ticker that was not produced because of the 1929 depression.
   Design was by Walt's group.  It had dual type baskets, one for letters and
   one for figures.
Black box stock ticker - did not have a model number.
Model 17 - Designed by Kleinschmidt, a Hellschreiber-like machine.  Don't
   know if it could interoperate with a real Hellschreiber.
Model 18 - Kleinschmidt designed page printer for Western Union.  Not
   manufactured.  It had a lot of parts in common with the 21-A multiplex
   tape printer, but was a simplex (i.e. start-stop) machine.
Model 19 - well known Teletype machine  There is also the DPE perforator,
   being a perforator-only version of the Model 19 keyboard.
Model 20 - fairly well known machine, up/low 6-level version of Model 15
   used for Teletypesetter
Model 21 -  The Western Union 21-A multiplex tape printer that has
   a few parts in common with Model 14
Models 22, 23, 25 and 27 - Walt doesn't remember anything about them.
   Probably machines that were designed but not manufactured. 
Model 24 seems to be an early version of Model 26, lacking some features
   of the latter.  Which means the typewheel positioning mechanism is
   based on the stock ticker.
Model 26 - fairly well known machine.  Was intended to be a low-cost machine
   for TWX service.  It turned out that by concentrating on one model, the
   Model 15, they could achieve the cost-reduction goal more easily.
Model 28 - well known machine.  10,000 of them were ordered by the Navy
   before it went into production.  Sales wanted to give it a new name or
   model number to indicate it was a complete break with the past; but
   Bell Labs insisted that model numbers continue in sequence.
Model 29 - One tradition says this was to be a 28-line replacement for
   the Model 20, and didn't sell.  Then there was the Model 28 IDP ASR
   set which a lot of us called the Model 29, rightly or wrongly.  But
   this is not inconsistent, since the IDP set used 6-level BCD
   computer code and the Model 20 replacement used 6-level TTS code.
Model 30 - Walt doesn't remember.  There was a lightweight page printer
   project for the military that was also an ancestor of the 32/33 line.
   The military project went nowhere because they chose the Kleinschmidt
   design, wanting to have a design they could own.
Model 31 - fairly well-known machine.  Lightweight portable tape printer.
   Used a type sector printing mechanism similar to SIGABA.
Model 32 - well known
Model 33 - well known
   Initially there was no interest from either the Bell System or Western
   Union in light-duty machines.  Teletype pushed ahead with development.
   The Canadians brought in European Telex, and W.U. saw this as an
   opportunity to connect with European Telex and compete with TWX, so
   they very suddenly got interested in the Model 32.  A Model 28 had a
   life of 10-12 years in 24/7 service, which meant that in typical TWX
   service it had a life of over 50 years.
Model 34 - Is this a Model 28 in Model 35's clothing?  Walt doesn't know.
Model 35 - well known
Model 36 -  Was this number saved for a 5-level version of Model 37?  Walt
   doesn't know.
Model 37 - fairly well known.  Aggregate motion printer produced in
   stock ticker and page printer versions.
Model 38 - fairly well known.  Up/low version of Model 33.
Model 39 - Walt doesn't know.  Was after he retired.
Model 40 - well known
Model 41 - Walt doesn't know.  Was after he retired.
Model 42 - Was this reserved for a 5-level version of Model 43?  Walt doesn't
   know.
Model 43 - well known dot matrix page printer.

Also - Teletype would make single copies of machines, or dummy machines,
   to demonstrate concepts.  Walt mentioned that in particular they would
   do this at the request of young Navy officers.  Old Navy officers already
   had their careers made, but younger ones were trying to make names for
   themselves and Teletype was happy to help them.

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jhaynes at alumni dot uark dot edu