I have Hikvision DS-7604NI-K1 NVR with 4 channels and 4 IP cameras (Exir economy level cameras), as well as Dahua KTP02 Video Intercom Kit.
The NVR has no RS-485 module, only motion detection methods give audible internal tone in the NVR.
I am thinking of having:
1. Door Contact Sensor
2...