Here started with a Ring Doorbell. It was easy to install and worked fine with my doorbell wires and interconnectivity to my OmniPro 2 panel
My set up here is a bit propietary and uses two Elk boards (Elk 930 and 924) to connect to the OmniPro 2 alarm panel.
I am not tethered here to my smart phone (never have been).
While I like the Ring Doorbell I cannot connect it to my home CCTV DVR so switching here to a
Hikvision OEM RCA Doorbell
Easy Installation: Connect the RCA Video Doorbell Camera to your existing doorbell wiring and to your 2.4 or 5 GHz WiFi network
Everything you need to install is included (requires an 8-24V AC transformer, existing working doorbell and electric drill)
Watch over your home with 3MP ultra high-definition video and live streaming; captures 50% more detail than full 1080p HD
Free recording of hundreds of events on the included 16GB micro SD card
Receive instant alerts when motion is detected using the free RCA Security All-For-One app and monitor your door from anywhere on your smartphone or tablet
Works with Amazon Alexa
Works with OmniPro touch (JPG captures)