Consider a simple native Call application. The Call application has two major states initialization & Idle. The different events are handled differently depending upon the states. The basic flow is as follows. In Initialize mode we have two sub-states inactive and cell search. At the start of call application, the inactive state triggers acquire cell event to search a network cell. If call application is unable to get cell then deactivate event will be generated and transition will happen to inactive state. In case some cells found then out of all one cell will be acquired and for this cell acquire event will be fired which will trigger transition from initialize to idle state. Once cell will be selected then at any point of time call create event can be fired to make a call here transition will happen from cell selection to call originate state. In case of call originate state call release/call failed events can disconnect call can be disconnected.

QUESTION 2

Auto Teller Machine (ATM) comprises of various states Off, Idle, Self-Test, Maintenance, Out of Service, and Serving Customer.

Initially the ATM machine is off state. However, when the bank officer turn-on the ATM machine, the ATM will perform a Self-Test. If the Self-Test is successful, then the ATM is in Idle state, otherwise, the ATM will be considered as failure and in the ATM now is Out of Service state, then the ATM system may trigger the "turn-off" or "shutdown" message to make sure the ATM is in off state.

If the ATM in the Idle, the system may trigger "service" message to show the ATM is in maintenance state. If the maintenance process if failed, the system is in "Out of Service" state. If the customer inserts the ATM card, the Idle states will become "Serving Customer" state. From Idle to the "Service Customer" state, it can accept the ATM card to activates the "Service Customer", cancel and back to Idle state, or failure which may trigger to the "Out of Service" state.

In the Serving Customer, the system read the ATM card, if valid then the system will verify customer or authenticates customer's password and account number. If valid, the customer is allowed to select transaction, and process the transaction.