The P-0920 has a “Chime” contact closure built into it. To utilize this feature, you simply need to connect the “NEGATIVE” or “GROUND” wire from the chime units power supply to one side of the phoenix connector on the chime contact. You would then run another wire out of the other side of the phoenix connector on the P-0920 continuing on to the connect directly to the chime unit. The “POSITIVE” wire from the chime unit power supply should NOT be connected to the P-0920, this wire should run directly to the chime unit itself. When connected in this way, when the front door station is pressed, the P-0920 will automatically trigger the chime as well as the phones.