When the input AC voltage is greater than 8V, the supply monitoring signal may control the LED indicator to display a green color along the peripheral edge 1040 of the doorbell button 1002, indicating that the input AC voltage is sufficient to drive the doorbell camera 106. In contrast, when the input AC voltage is not greater than 8V, the supply monitoring signal may control the LED indicator to display a red color along the peripheral edge 1040 of the doorbell button 1002, indicating that the input AC voltage is insufficient to drive the doorbell camera 106. Referring to FIG. 10D, in some implementations, the bypass unit 1012 may also function as a voltage meter to determine whether the transformer 1010 can provide a supply voltage sufficient to drive the doorbell camera 106 which normally consumes more power than a conventional doorbell. The bypass unit 1012 includes a voltage monitoring unit 1012A, an LED indicator 1012B, and bypass circuit 1012C. The supply monitoring signal is generated by the voltage monitoring unit 1012A of the bypass unit 1012, and the LED indicator 1012B is located in the bypass unit 1012. The LED indicator 1012B sends a visual message to the user to indicate whether the input AC voltage is low with respect to the supply threshold. Likewise, in some implementations, the remote chime 1006 may be configured to ring differently based on the supply monitoring signal, thereby indicating whether the input AC voltage is sufficient to drive the doorbell camera 106. Arrangements shown in FIG. 10C may sometimes be utilized to simplify a process of setting up the doorbell camera 106. The bypass unit 1012 may be connected to the transformer 1010, the doorbell chime 1006 and a conventional doorbell 1024 i.