A Traditional Landline Telephone System Mainly Contains Below Three Parts:
1. A Hook Switch, Which Connects And Disconnects The Phone From The Network;
2. A Speaker, Which Can Be Used Without Picking Up a Handset And Several People Can Participate In a Call At The Same Time;
3. A Microphone, Through Which Sound Waves From Your Voice Compress And Decompress The Granules, Changing The Resistance And Modulating The Current Flowing Through The Microphone.