I get to work and unlock the door with my Key Card/Fob. My phone automatically changes from Out of Office to Available. (Perhaps my Access Control system would need to know my extension and send the instruction to 3cx that user <Ext> just arrived. If <ext> has Presence by Access enabled, then their presence in 3cx changes to Available.) This would be an option for each extension, within 3cx Phone, to enable/disable.