[GreenKeys] Navy abandons M28 compatibility

[Jim Haynes]

> In a message dated 6/8/2013 11:33:52 A.M. US Mountain Standard Time,
> nagle at animats.com writes:
>         That was originally for backwards compatibility with Morse
>       code.
>       Morkrum's first machine, the Blue Code machine (1910) had upper
>       and lower case characters, with three shifts, LOWER, CAPITALS,
>       and FIGURES, and a 3-row typewheel.  But printing telegraphs
>       were originally used only on main lines, so the same message
>       would also go over a Morse link.  Lower case info was lost
>       in Morse transmission.  Western Union asked for machines
>       without lower case, and that's how it all started.
> 
The customer for the Blue Code machine was Postal Telegraph Co.  Their
messengers wore blue uniforms and the company's color scheme emphasized
blue.  The Green Code machine was made for Western Union.  Their
messengers wore green uniforms and the company's color scheme favored
green.  Indeed various shades of olive green.  This has made me wonder
if the company bought a bunch of paint war-surplus after WW-I and used
it on their equipment.  Later on they adopted a gray-green color fairly
similar to what Teletype used on the Model 28 line.