As simple as stick a QR-CODE near your entry door. This is all you need to enable Virtual Door Phone on your home/office location(s). Visitors can directly scan a QR-CODE with their smartphone, or simply enter a unique Dorro Phone Code to www.doorpass.eu, and they will instantly connected to your Virtual Door Phone where you can easily chat with them. Never miss an important visit or delivery to your locations. Please note visitors are NOT required to install any app on theri smartphone.