This slide set is a short presentation that helps give the idea of a finite state machine. The phone is an example of a finite state machine. It has state, and events transition it from one state to another.

2. Waiting The phone is idle and waiting for something to do

3. Waiting Dialling Event: Start calling You start to phone someone

4. Waiting Dialling Wait for answer Event: Start calling λ You dial a number and start waiting for someone to answer the remote phone

5. Waiting Dialling Wait for answer Conversation Event: Start calling Event: Pick up λ Someone answers the remote phone and you talk to him (her)

6. Waiting Dialling Wait for answer Conversation Event: Hang up Event: Start calling Event: Pick up λ You finish your conversation and hang up

7. Waiting Dialling Wait for answer Conversation Event: Hang up Time out Event: Start calling Event: Pick up λ If nobody answers the remote phone, you hang up and the phone becomes idle again

8. Waiting Ringing Dialling Wait for answer Conversation Event: Hang up Time out Event: Incoming call Event: Start calling Event: Pick up λ If there is an incoming call then the phone starts to ring

9. Waiting Ringing Dialling Conversation Wait for answer Conversation Event: Hang up Time out Event: Answered Event: Incoming call Event: Start calling Event: Pick up λ If you answer the phone then you can talk to the remote person

10. Waiting Ringing Dialling Conversation Wait for answer Conversation Event: Hang up Time out Event: Answered Event: Incoming call Event: Start calling Event: Pick up Event: Hang up λ You hang up when you finish talking and the phone becomes idle again

11. Waiting Ringing Dialling Conversation Wait for answer Conversation Event: Hang up Time out Event: Answered Event: Incoming call Event: Start calling Event: Pick up Event: Hang up λ If nobody answers a ringing phone it will go back into an idle state Time out