[GreenKeys] Teletype Model 27?

[Thalia Archibald]

A mention of a "KSR-27 teletype" caught my attention in these memos on the
formation of the DEC Computer Museum in 1979. I'd never heard of this model and
I'm surprised it's not one of the more typical models used with a computer. Does
anyone know anything about the Model 27?

    CONFIGURATION LIST

    PDP-4 #1

    1 central processor
    8K memory
    1 line printer (Analex)
    2 card readers (Burroughs)
    4 tape units (Potter - I think)
    1 card punch interface (IBM)
    1 Dectape control
    2 555 Dectape transports
    1 KSR-27 teletype
    1 paper tape reader/punch

    https://www.computerhistory.org/collections/catalog/102740424/

This site on telegraph equipment says

    Model 27 - referenced in museum book - says that is the model number for
    TT-4/TG (XC-2) a proposed military machine with a typing unit like a Model
    26 and a keyboard like a Model 31.  Says only 10 units were made.  Note that
    the production TT-4/TG is a Kleinschmidt machine.

    https://prc68.com/I/Telegraph.shtml

Thalia