Terminology of condition (state) used to representation one condition about total line from busy bundle (occupied) in one time interval. So that contemplated with state probability is state duration probability to go on in one time interval (1 busy hour).
To make easiest representation about state and the change, can be used State Diagram Form.
If to exist incoming call or to exist occupation ended, then will occur state change (transition), from one state to the other state.
