1| Automatic switching system can be divided into two parts. They are :1.Electromechanical and 2.Electronic.

2| In electronic switching system, we use control function and logic.That's why information are stored. Then that stored information are provided & information can be send.It's called Stored Program Control(SPC)

3| Electromechanical switching system can be divided into two parts:

1.Steb - by - step  and 

2.Crossbar

4| In space Division switching system, dedicated and exclusive switching path should be established.

5| in time division switching sample values of speech signals are transfered at fixed intervals.