Optionally, the message may include a visual message displayed on the bypass unit 1012 by an LED indicator 1012B according to one of a set of predetermined visual patterns. In some implementations, the message presented to the user may include a ring of the remote chime 1006. 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.