In the Building G , The Owner want to use the fingerprint device to accept into the elevator. For example:
If Person A live in floor 4, then he/she should enroll his finger to fix with floor 4.Then when he identify his finger, the device will control the elevator to accept into floor 4.

And if person A want to go to floor 10 to see his friend. then he should identify his finger and then change the NUMBER.

But if the people can not identify his finger, then he can not input the number.