1) this automatic switching system it does not hamper any privacy and we do not need any third party person to connect our communication 

2) in Rotary dial system there are two method are used :

  # pulse dialling 

.  # multi frequency dialling 

3) Strowger was invented automatic switching system. In automatic switching system, human operator doesn’t exist actually. 

 4) There are many advantages of automatic switching system:

# In a manual exchange, subscriber needs to communicate with the operator and a common language becomes an important factor.

#.Establishment and release of calls are faster in automatic switching system. 

5) A rotary dial telephone uses the following for implementing pulse dialling :

# Finger plate and spring. 

# Shaft, gear and pinion wheel.

# pawl and ratchet mechanism. 

6) A rotary dial telephone is classified either as camp type or trigger type, depending on whether a cam mechanism or a trigger mechanism is used for operating the impulsing contact.