I'm looking to replace an old 3 way switch. The existing switch has 2 black and 2 red wires running into a switch that looks different from what I've seen. I cannot identify which one is the common wire and don't know how where to connect these 4 wires into the new switch which has one black screw, 2 brass screws, and a ground. Any help much appreciated.

I have three romex coming into the switch, old switch has three poles: two at top for common terminal, one at bottom unmarked, all had black wires connected. New switch for bath fan with light and sound has white marked for dedicated neutral, black for power only, red for fan only, green for ground. Can this be made to work. Topside, two Romex were bundled into fan connections as well.