The output can be turned on or off externally
using a switch. The analog control connector
can be set to turn the output on from a high or
low signal. The voltage across pins 19 and 20
are internally pulled up to +5V ±5% @ 500uA
with 10kΩ pull-up resistor. A short (closed
switch) produces a low signal.
When set to High = On, the output is turned on
when the pins 19-20 are open.
When Low = On, the output is turned on when
pins 19-20 are shorted.