[GreenKeys] Free to good home - M28 tape printer for 3/8" tape

[Jim Haynes]

I believe the M37-technology ticker was called "900" by the NYSE because
it was 900 characters per minute.

The titles of the manuals for the 1931 ticker have it as
"Typewheel Tape Printer (Ticker)"  For that matter, I don't know if the
21-A printer actually had that as a model number.  21-A is a Western
Union model number, and the Teletype manuals call it merely "Multiplex
Tape Printer (W.U. Model 21-A)"

There are two manuals for the ticker, 136B and 137B, and the latter says
it is for units with serial number over 1000.  So maybe the initial 
production run was 1000 units - or maybe not, maybe they just arbitrarily
started the serial numbers over again at 1000.

Then manuals I have came, I think, from the John Sheetz material. 
Handwritten on the front of the books is "M23"  which could mean
that it was called a Model 23.  I made a list of Teletype model numbers
one time and asked the late Walt Zenner to fill in the blanks - models
22, 23,25 and 27 he didn't remember anything about them and thought
they might have been machines that were designed but not manufactured.
He mentioned a type bar ticker that had separate type bar sections for
letters and for digits, on opposite sides of the tape.  This was not
manufactured.

I was looking at the parts book, motor and gears, to determine the speed
of the older ticker.  It shows two different gears for use with the
sync motor, labelled 5A and 4A in parentheses.  The ratios work out to
shaft speeds of 750 RPM for the 5A and 428.5 RPM for the 4A.  The manual
says the receiving shaft is 1/12 faster than the transmitting speed (so
that the selector has time to stop between characters)

Running those numbers out seems to say that the 4A was running about
392 chars/minute and the 5A was running about 690 chars/minute.  Seems
like I have heard the NYSE call the older ticker the "600" ticker
for 600 chars/minute.  That's 100 wpm, so Teletype had a 100 wpm product
before the Model 28.

FWIW

jhhaynes at earthlink dot net