1. Advantage of Automatic switching system: 

a) The subscriber does not need to communicate with the operator.

b) Greater privacy is obtained.

c) Establishment and Release of calls are faster.

2. The two method for the mechanism to transmit the identity :

    a) Pulse Dialing

    b) Multifrequency Dialing

3.  G = Governo

     GW= Gear Wheel

     IC = Impulsing Cam

     ICO = Impulsing Contact

     MS = Main Shaft

     P = Pawl

     PW = Pinion Wheel 

     R = Rachet