Door camera similar to Ring option onto NVR

[Mr_Freeze]

Hi Everyone,
I have an up and running DS-7608NI-I2-8P with 8mp Turrets and I now want to cover the front door with something like a Ring doorbell.
Ideally an ip camera that will work with the NVR to give full back up.
It should have audio in and out and also what I’d like to do is use the existing door bell via a relay to provide an alarm input.

Has anyone done this?
What did you use, what kind of results did you get?
Recommendations anyone on what would work?

 

[fullboogie]

I don't know if we are allowed to refer to other websites, so I'm taking a chance. Here's a thread on another site that details this issue. Does not look easy. If Dan/Phil prefer, I can send you this link via PM.

Hikvision doorbell camera - DS-KB6003-WIP