XR100 reset question

We have a DMP XR100 alarm control panel installed here, and we also have a remote control and monitoring system in place. This allows us to remotely arm and disarm the security system and monitor whether the system is armed or disarmed from a remote location.
There also used to be a “reset” relay connected that allowed us to reset the fire alarm once we had confirmed if it was a false alarm. I can’t for the life of me figure out how to reconnect it after we moved some equipment here.

We’ve had alarm techs on site who just scratch their heads, shrug their shoulders and say they don’t know, but I know it used to work, so there ought to be a way to make it happen again.

Speaking in general, does anyone know if I can just momentarily short across the fire alarm zone wires, momentarily break and re-make the connection, or do we have to connect to a different zone and program it as a reset channel?