FIG. 10D is a block diagram of a doorbell camera system that has a voltage monitoring unit in a bypass unit in accordance with some implementations. The doorbell camera system 1000 includes a doorbell camera 106 having a doorbell button 1002, a camera module 1004, an LED indicator, a speaker, a microphone, a processor and memory including programs executed by the processor. The camera module 1004 further includes a lens assembly 704 and an image sensor array that are configured to capture images at a premises, and a wireless transceiver that is configured to exchange data with a remote server over one or more wireless communication networks. The doorbell button 1002 is configured to trigger a remote chime 1006 in response to a user press on a button top 702. In some implementations, the LED indicator is configured to illuminate through a peripheral edge 1040 of the doorbell button 1002 that surrounds the button top 702. The doorbell camera 106 is electrically coupled to the remote chime 1006 via a bypass unit 1012 powered by a transformer 1010 that provides an input AC voltage e. g. , by converting a mains power supply of 110V to the input AC voltage of 8V, 10V or 12V. The remote chime 1006 is configured to ring in response to a press on the doorbell button 1002. In some circumstances, a conventional doorbell is electrically coupled to the remote chime 1006 that is further coupled to the transformer 1010.