[GreenKeys] Question about the voltages

[Don Robert House]

Sheldon,

NO 520vdc!  Normal limits on a telco cable pair is 200 volts.  All  
continuous voltages are supposed to be negative to avoid electrolysis.  
The C.O. had a -130vdc supply and a +130vdc supply  wired in series to  
serve a machine that was "wired out of limits"  temporarily until a  
new design could get the current source closer to the machine...  
usually a 43A carrier system channel and/or a 130 telegraph subset at  
the customer location.

To operate the selector magnet properly and to make sure the machine  
sent a good signal we would install a Wave Shaper which was a multi- 
tap set of coils to compensate for all of the inductance on the long  
loop.  I still have my 164C4 Telegraph Distortion Scope.

Don
K9TTY