In the following the abstract systems behavior will be described. The term "automatically" describes the
behavior of a device that is done without control of this software system. The ticket machine will
automatically print the time on the ticket if a ticket is provided. The card reader in the ticket machine
automatically reads a card that is entered. The ticket reader reads a ticket or a monthly ticket. It reads the
ticket number and whether or not it is a monthly ticket automatically. The induction loop is in two states:
A car is present in the induction loop at that moment or not. If the state changes, a signal will be sent to
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the PGCS. The gates have two states: open and closed. It takes some time to change the states. The state
display shows two states: full and vacancies. This is according to the number of available public parking
spaces in the parking garage. (The state display is not relevant for the drivers that own a monthly ticket.)
With the numerical keypad there is the possibility of entering the number of total and reserved parking
spaces. At the cashier the fee is paid. The cashier then notifies the system of the ticket number at this
time. The cashier is not controlled by the software system.