[GreenKeys] Designer Question RS-232 to Loop interface

[Lester Veenstra]

It seems that the keyboard interface is in parallel with the LED diode going
back to the RS-232 interface.  The (non-60ma) loop formed from R6 (10K 2W)
goes through the diode to the loop negative side. The keyboard contacts also
go from the loop source (R6) to the loop negative return.

 

 

Schematic of interface device

 

Lester B Veenstra  MØYCM K1YCM W8YCM

 <mailto:lester at veenstras.com> lester at veenstras.com

 

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