[GreenKeys] Teletype Model Numbers?

[jhhaynes at earthlink.net]

I would guess that the Mode. 34/35 plate, since you say it is on the
cover, is something of a marketing gimmick.  Model 28 equipment has
a similar name plate for a similar reason.

Internally, Teletype used the model numbers colloquially but used
letter codes officially.  Thus the LKPE 500BSF is
L means Model 28 line, and also 29 and 34 and 35
KPE says it is a keyboard perforator.  500BSF is a particular
model.  When I was around there the 5-level stuff had short model
codes, e.g. LP6 for a Model 28 printer, and the 8-level stuff had
numbers starting with 800, so LP801 would be a Model 35 printer.
So it looks like they decided to start the 5-level stuff with 500
codes.  Typically the number 500 is the basic model and then the
BSF means some specific features of that unit.  Like a Model 28 keyboard
would be LK something and then some letters on the end specifying the
keytop arrangement.  LP would have letters on the end for the type box
and stunt box specifics.

Equipment made for the Bell System would use the model numbers on
nameplates rather than the Teletype codes.  So a typing unit
instead of LP nn  would be  28A typing unit.

In addition to L for model 28/29/34/35 they used B for Model 15,
F for Model 14, Y for Model 37, and I forget what they used for
other model lines.  The high speed stuff didn't have these model
line prefix letters.  There's the well-known BRPE punch, and the
later DRPE punch, and the BX and CX and DX tape readers.  I don't
know if there was an ARPE and a CRPE and an AX.

Then there are the VCL and VSL codes.  Originally to order a Model
28 KSR for example you had to order the keyboard LK, the typing unit
LP, the electrical service unit LESU, the motor LMU, and the cabinet
LAC and put them all together when they arrived.  Sometime in the
early 1960s they decided to define VSL codes for complete sets that
were popular combinations of all the parts.  You could pick out a VSL
that had the combination of keyboard and printer and other things
you wanted and order that single number and have it arrive all put
together.  VCL was a similar idea for things that were considered
components rather than complete sets.




jhhaynes at earthlink dot net