I am trying to understand how Access Control system work in this link https://kintronics.com/long-range-access-control-systems-work/

Each device has different credential I don't understand how the system read and identifies each vehicle ?

 

Do you understand how door access control systems work?

 

It's an RFID tag device, the transmitter sends out a high frequency Khz signal which powers the tag and transmits it's signal back to the receiver.
Each tag has it own tuned circuit and chip giving it it's own unique ID, .