QR or Bar Code access control

[networkcameracritic]

We have a need to send guest passes out so people can print them or show them on their phone and the reader would grant or deny access. We currently have access control using HID Edge and VertX and RFID tags, so this would supplement this. Also, we have Doorking phone entry dialers if it can integrate with that and we have cameras at those points recording on Milestone XProtect, so maybe that can read codes, send an alarm out to the entry system to trigger the gate to open.

Any ideas?