[GreenKeys] Police teletype

[Jim Cooper]

On 18 Dec 2019 at 18:05, Jim Haynes wrote:

> The solenoid seems like a crude way to
> handle the function, but maybe the
> customer wanted to be able to control
> it remotely as well as from the
> front of the machine. 

remember, back then they did not have 
electronic logic and switching ...  all selective 
coding was done with function levers and 
tiny switches in the stunt box.  If traffic 
for multiple stations was sent on the same 
circuit, the special code(s) for the local station 
were detected mechanically in the local stunt box 
and a switch closed to activate something like the 
solenoid, which would then disable the print 
suppression (double negative!) ...  local reperfs 
were controlled in the same way, with special 
codes decoded by the stunt box. 

Back in the late 60s I designed an international 
switching system which took up an entire floor 
in the Pan Am building in NYC for the Pan Am 
communications system.  Every M-28 in the place 
used many such stunt box features to turn things
on and off, including R/T tape relay cabinets that 
sent traffic off to other circuits, etc. !!   That was 
quite a project for a mid-20-year old tty engineer! 
(Circuits were lease tty circuits with ITT World Comm). 

w2jc    ex-w2bve