The R2X doorphone can support ONVIF Profile S, which can be compatible with NVR.

A 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.

1. Go to R2X's Web - Intercom - ONVIF to configure it. Choose the ONVIF mode to be “Discoverable.”
2. Users can set its username and password, the username and password is admin/admin by default.
3. Go to NVR's Web to add the R2X doorphone.