A "dry contact input" generally expects that its two contacts will be shorted to each other to activate it -- and NOT shorted to anything else.
An "open collector output" is one that is open-circuit when inactive, and shorted to ground when active. This type of output is usually assumed to be an NPN transistor (or its equivalent), and is intended to sink current to ground only.
In general, it is NOT OK to connect an open-collector output to a dry contact input, unless you know by other means that a) the dry contact circuit is DC and b) it's safe to connect one of the dry contact inputs permanently to the open-collector circuit's ground.
Just as an example, consider an ordinary HVAC thermostat. The heater control circuit usually runs on 24 VAC, and the dry contact in the thermostat can safely activate it. But the AC voltage would probably damage the circuitry of an open collector output. Or, if the latter includes a diode for reverse-voltage protection, it would either be half-on all the time (shunt connection) or only half-on when active (series connection).