Doorbell Installation Issue: Old Doorbell had 4 wires instead of 2

I am trying to install my Video Doorbell Pro, however have run into an issue in that the old doorbell at our new home has 4 wires (white, red, green & black) instead of 2.  I have tried all of the possible combinations of these 4 wires and have yet to get any response from the doorbell.  Has anyone encountered a similar situation and been able to install the doorbell?