The essential electromechanical functions that make a phone work are quite simple and straightforward. This explanation describes the processes that make a landline phone work. The processes that make cell phones work and that allow Voice over Internet Protocol (VoIP) phones to work are a little more complicated and require radio waves and Internet Protocol (IP). The basic principles for making any phone work, however, are the same.
To make a landline phone work, two copper wires must transmit two things:
Signals and voice. The two wires, usually coated in green and red, are the heart of the process that makes the phone work. While the phone is resting on the hook or in its base, a capacitor inside the base of the phone limits the amount of electrical current that flows to the ringer, actually a chip inside a small speaker. The capacitor prevents a short in the wires and the local telephone exchange equipment recognizes that the telephone is on hook.
For the telephone to function correctly, the sound must be conveyed along the same wires that activate the ringer. The handset of all telephones contains a microphone that allows you to transfer sound impulses into electrical impulses. The other integral part of the receiver, the receiver, converts the audibly modulated electrical current into sound waves and the voice is heard. The transmission and reception of voice, therefore, depend on both sound waves and electrical pulsation.
When the phone is in its base, only the ringtone, the chip, is electrically connected. When the phone receives an incoming call, the local telephone exchange sends a surge of high voltage alternating current (AC) to the base switch. This surge cuts out the capacitor and the base integrated circuit (IC) causes the phone to ring. For phones in the United States, this increase is usually in the 20 hertz (Hz) range. The telephone receiving the call is dialed via the dial tone pulses (DTMF), the buttons on the caller’s telephone keypad. When the transmitting and receiving receivers are raised, the switch in the base transfers electrical surges from alternating current to direct current (DC), allowing the transmission of the voice on the two wires. The two cradle switches then excite resistance shorts across their respective wires, producing a line signal at the transmitting end and activating the chime at the receiving end.
The primary telephone cables range from telephones to telephone sockets and entrance boxes of the house or building. From there, telephone cables strung on the ubiquitous telephone poles along the street relay calls to the local exchange. From the local exchange, fiber optic lines, radio transmissions and, for long-distance calls, satellite transmissions carry a call to its destination where it returns within the two copper wires.
Radio waves are used to make a cell phone work properly. Internet protocols (IP), network digitization and packet switching are used to operate the VoIP phone