[GreenKeys] Model 28 signal lines

[Jerry Murphy]

Greenkeys:

Here's a link to an article in a 1955 issue of the Bell System Technical 
Journal about speeding up the operation of relays by applying dual voltages
to the coils.  The article shows a very simple fix for speeding up relays
quite dramatically. 

Here's the link:

https://ia801901.us.archive.org/29/items/bstj34-6-1225/bstj34-6-1225.pdf

In the article, the authors describe how standard central office voltages 
of 48 and 130 are used with a minimum of additional components to make the 
relays and crossbar magnets operate faster.  

I would think that this technique is also applicable to selector magnets.

Jerry Murphy