By these means, voltage compatibility of the doorbell camera 106 may be determined and known to the user of the doorbell camera 106 before the doorbell camera 106 is installed, thereby avoiding installation of the doorbell camera 106 when it is not even compatible with the supply voltage provided by the transformer 1010. More details on the method 1500 implemented by the bypass unit 1012 are explained above with reference to FIG. 10D. FIGS. 11A and 11B include a top view 1100 and a cross sectional view 1140 of a doorbell camera 106 in accordance with some implementations, respectively, and FIGS. 11C 11E are three exploded views of a doorbell camera 106 in accordance with some implementations.