The ADC-VDB770 can support up to two digital or mechanical chimes simultaneously by using two power modules. The chimes themselves must be wired in parallel rather than in a series. 

For more information about enrolling the ADC-VDB770, see Alarm.com Video Doorbell (ADC-VDB770) - Installation Guide.

Wire the ADC-VDB770 to two chimes

Wiring

Diagram

On the first power module, attach the white wires interchangeably to the FRONT and TRANS terminals on the chime. On the second power module, attach the white wires interchangeably to the REAR and TRANS terminals on the chime. Attach one of each of the power modules to the transformer using a wire connector. Attach one of each of the power modules to the ADC-VDB770 using a wire connector. On the ADC-VDB770, attach the remaining wire to the transformer.