[GreenKeys] What the heck is a "Selector Key"?

[kf9nz at juno.com]

 I am sorry I have been offline for a couple of weeks and missed this
thread.  I am quite familiar with  60 type selectors, and can tell you
more than you want to know about them.   The 60A key and the 60C did
exactly the same thing -generated the code in exactly the same way.   The
60A mounted in a desk top base with contact springs so that a spare key
could be installed quickly.  The 60C was made to mount in the stiles of a
telephone switchboard, and the motor ran on 48VDC as opposed to the 60A
which ran on 120 AC.
        Typically the 60A key was used by a Train Dispatcher (which I was
part time for a while) to signal the train order operators (which I was
for 12 years) on his piece of railroad.  The Dispatcher's line was a
party line, sometimes over 200 miles long.  Each station where there was
an operator had a 160 or similar selector set which had selector receiver
60AP or BP in it.   When the Dispatcher needed to talk to an operator he
punched two  red buttons and then one black button.  The numbers on the
red buttons governed the first and third strings of pulses and the middle
string made up the difference.  The total number of pulses was always the
same.  Only the number of pulses between the pauses was different.  The
selector key then operated two hefty relays.  One turned the 250 VDC on,
and the other was a pole changer.   The polar DC signal was then fed into
a humoungus transformer primary.  The secondary was connected to the
line.  The result was (nominal) 3 -1/2 cycle AC which caused the polar
armature of all the selector receivers on the line to operate and drive
the code wheel you can see in Jeff's videos.   Small pins fitted into
holes in the code wheel determined if the code wheel  was held in an
advanced position by an arm, or fell back to the starting position and
thus never reached the ring position.     After 12 years as an Operator I
became a comm maintainer/lineman and fixed the durn things.   To think
that two NOS keys still exist is equivalent to finding a 1920 automobile
brand new-never-been- run.  I am ignorant of the use of 60 type selectors
being used in TTY selective calling, but if so I am enlightened.  I can
tell a few stories about this stuff, but it isn't very relevant to
Greenkeys which is what we're here for.  Somewhere I have some original
Western Electric booklets that describe the system in detail.    

Frank
On Tue, 3 Mar 2009 21:15:06 -0600 "Derek Cohn/WB0TUA"
<vibroplex at mindspring.com> writes:
> Hi Gang,
> 
> I picked up a box of "teletype" parts recently and inside were two 
> NOS boxes.  One was marked "Selector Key 60A" and the other was 
> marked "Selector Key 60C".  The boxes are dated May 1957.  I've 
> posted photos on the web to help with the ID:
> 
> Here is the selector 60A:
> 
> http://www.mindspring.com/~vibroplex/selector60a.jpg
> 
> Here is the selector 60C....it includes an envelope with some little 
> part in it (I haven't opened the envelope):
> 
> http://www.mindspring.com/~vibroplex/selector60c.jpg
> 
> I was planning on tossing both of these on eBay...if anyone on the 
> list is interested in these, please let me know.
> 
> 73 and thanks for any help you guys can give me,
> 
> Derek Cohn
> Morse Telegraph Club - Alton Chapter
> Office UD, Sine DJ
> Amateur Radio Station - WBØTUA
> 1969 Brunswick M274A5 Mechanical Mule
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