door camera system
What is the best front door camera? What is the best wireless doorbell camera?

Network video recorder (NVR) is a specialized computer system that includes a software program that records video in a digital format to a disk drive, USB flash drive, SD memory card or other mass storage device.

front door camera. Blink XT2 Outdoor/Indoor Smart Security Camera with cloud storage included, 2-way audio, 2-year battery life – Add-on 
These are the best doorbell cameras we've tested for keeping tabs on your However, they usually interact with other system components such as door locks,