Garadget connection to GDO-7 v2 Securalift garage door opener is via terminals marked OSC and GND.
Quote from the manual:
GND - Common ground for accessories.
OSC is used for the connection of a wired switch (momentary contact). This switch can then
be used to open, stop or close the door. Install the wall switch in a location where the switch is out of
reach of children and the garage door is visible.