[sdiy] How do duophonic keyboards work?

[Phillip Harbison]

How do duophonic keyboards such as the ARP Odyssey generate two control 
voltages? I'm looking at the Odyssey schematics and see a resistor 
ladder like in my Moog Satellite, but the wiring seems strange to me. 
With a monophonic keyboard I believe the connections are +15V to the top 
of the ladder, ground to the bottom, and the CV bus. On the Odyssey the 
connections are labeled "KYBD HI" to the top, "KYBD LO" to the bottom, 
and the CV bus. How does this get me two control voltages?

Yes, I owned a Satellite. I was in 10th grade and that is all I could 
afford. Let the guffaws begin. :)

-- 
Phil Harbison