[GreenKeys] M14 Receiving Distributor

[Jim Haynes]

I don't know if there was a receiving distributor after the Model 12 and
before the Model 28.  Western Union certainly had some of their own
design.  For regeneration there was a mechanical regenerative repeater.
There's a picture of it in the AT&T Long Lines "Principles of Electricity
Applied To Telephone and Telegraph Work", 1938 edition.  A later edition
shows an electronic regenerator using vacuum tubes.

Prior to the Model 28 there was the SOTUS - Sequentially Operating
Teletypewriter Universal Selector - which had a selector like the
Model 14/15 line and the ability to detect individual characters and
sequences of characters.  There was a Model 28 equivalent, essentially
a Model 28 printer with the front plate mechanism removed so that
there was no printing and only the stunt box functioned to operate
contacts on sequences of characters.

Before either of those there was a machine which I only know about
through mention in a Teletype correction sheet.  It was apparently
a Model 14 printer without the ability to print.  Contacts could be
mounted over the pull bars to detect individual characters; but
detection of sequences required relays external to the machine.
A similar thing was used by Western Union with their Model 14 (2B)
printers, and with the FRXD machines.  FRXD machines came in both
typing and non-typing versions.