The technics is the logical 0 or 1.
A logical 0 is 0 Volt Direct
A logical 1 is 12 Volt Direct Current.
( 0 Volt and 12 Volt as example )
Think of a battery with switch and lamp.
There are two possibilities.
The switch is open, the lamp is off.
That is the logical 0.
The switch is on, the lamp is on.
That is the logical 1.
A signal has two possibilities.
A red or green signal.
( We take only signals with a red and green lamp )
A point has two possibilities.
A bow or right on position.
A relay has two possibilities.
In rest or is "up".
A signal we can operate with a switch ( or with the computer ) and a relay.
When the signal is on red, you can switch of the
current of the rails for the
signal through the relay.
If you use MARKLIN HO low voltage for handling a point an electronical
circuit with relays.
The electronical circuit with
With this you can operate a MARKLIN point
with a switch or the outputcard.