https://www.hackster.io/hackershack/smart-doorbell-video-intercom-system-e5aa61
Raspberry Pi-powered hardware that notifies you when guests arrive and lets you talk to them on your phone through internet calls. Find this and other hardware...
video intercom systemsmart doorbellhacksterio
https://www.securityinfowatch.com/video-surveillance/video-intercoms/product/21073547/alpha-communications-alpha-communications-alphatouch-smartphone-video-intercom-system
System provides audio and visual calls without the need for traditional video-intercom monitors and their related wiring
video intercom systemsecurity infoalphacommunicationssmartphone