Mine is an ATA Securalift.
Look at the manual for yours on page 8 - terminal block 01 with
24V PWR is used to power devices such as:
PE (Input) for photo electric beam for safety and Auto-Close function.
LGT (Input) allow hard wired external trigger for the opener’s courtesy light.
O/S/C INPUT is used for the connection of a wired switch (momentary contact). This switch
can then be used to open, stop or close the door.
If you put a voltmeter probe on the LGT / Light pins (ground the other probe), while you are opening or closing the door, you will see that there is a fluctuating current on the relevant pin, depending on whether opening or closing. - Correction - use the LGT pins, not the OCS pins to monitor status.