[GreenKeys] Anyone familiar with the Model 29 (Twenty Nine) Teletype?

[Jim Haynes]

What was called Model 29 was originally designed as a six-level machine
to replace Model 20 as an up/low case monitor for Teletypesetter. 
Apparently nobody wanted any.  Later it was turned into what was 
officially called Model 28 IDP [Integrated Data Processing] ASR set,
which used one of the IBM six-level BCD codes.  These were supposedly
made for internal Bell System use only.  AT&T did not want to be accused
of favoring IBM over the other computer companies, although the others
used slight variations of the IBM BCD code and could have been served
equally well with typebox changes.  Also AT&T was interested in promoting
ASCII and therefore discouraging any continued use of the six-level BCD
codes.

It is apparent that some of the Model 29 sets escaped the Bell System
somehow.  When I worked for G.E. Computer Dept. 1966-68 there were
some Model 29 typing units around and a young man was converting them
to 8-level ASCII.  Later there was a surplus business in Oakland CA that
had the remains of some RCA computer and a bunch of Model 29 RO printers.
A housemate of mine bought several, converted the typing units to ASCII,
and sold them to a dealer in the Los Angeles area.  I don't remember what
he did with the cabinets.  The converted units were equivalent to Model 35
typing units.