The second generation of Safire video intercom systems does not allow monitor call (short press) and PC call (long press) at the same time.
But we can decide if we want that button to call the PC or on the contrary call the monitor, in a mutually exclusive way. You can choose it here:
This menu, as you can see, is located in the Safire Control Center itself within the remote configuration of the device, after having added it to the software.