[amsat-bb] what positioner interfaces exist?

[Eric Fort]

I've been looking at how tracking hardware interfaces to positioner
hardware.  There seems to be multiple ways used to induce movement and
multiple ways to sense/track position.   some seem to require up,
down, right, left (4 bit) control signals along with an analog voltage
provided for position indication while others may just count pulses to
track position and may use unipolar vs bipolar motors.  I've also seen
syncros and steppers used.  What is being used and what is common for
positioner interface requirements?  What means are used to sense/track
position and what signaling is needed by various systems to induce a
change to that position?

Thanks,

Eric
AF6EP