A:AnswerIf there are more than one cameras, and they are placed conveniently in the home, it will work fine your cell phone also rings as the doorbell does. Along with whatever else you think, smart TVs, fire devices, etc..
A:AnswerYou can purchase the Sync Module and save data to a flash drive to save on monthly cost. You will loose some live functionality if you do. If you choose to use the Cloud services it is $3.99 per camera per month, with generous discounts for annual and multi camera accounts.
A:AnswerThe Blink Video doorbell will not fit in you peephole, but can be installed anywhere near it to behave like one. It is a small rectangular box that has a good look and can display the video on your phone or other compatible assitants (mostly Amazon)