[josemrb]

I've built a few systems for low-cost airlines in South America. There shouldn't be a lot of difference with bigger airlines around the world.

The boarding software usually checks that:

  - The boarding pass is valid (checksum)
  - The flight state is correct e.g. 'boarding' and 'open'
  - The passenger did check-in
  - The passenger haven't boarded yet

More advanced implementations can match the gate with the flight, this is optional.

The beep usually is a response from the reader indicating that the code has been read successfully.

The result of the operation is displayed in a screen and the attendant has to read it and act accordingly.

[kalleboo]

> The beep usually is a response from the reader indicating that the code has been read successfully.

In Japanese domestic terminals, the gates are definitely more advanced - they play a different chime depending on your frequent flier status.