- A telephone call starts with the dialer. When you dial the phone numbers on the keypad, the phone sends the numbers as a frequency through a frequency generator. This tells the phone call where to go on the other end of the line.
- The microphone in the handset of the telephone is the next step of a phone call. The microphone takes the wavelengths of your voice as you speak and transfers them into the wires. The sound travels through the wires through a duplex coil, which prevents you from hearing what you're saying through the speaker end placed against your ear. The wavelengths are then sent through a hook switch that connects your call when it's released, and disconnects a call when it's active. The sound signal then goes from the hook switch to your phone jacks on the wall.
- For the telephone call to get to its recipient, the sound must travel through a host of wiring and telephone stations to get to its destination. From your phone jacks in your home runs a pair of copper wires. There are a pair of copper wires for each telephone line you have in your home. These wires run out of your house and to a telephone box on your street. All the wires from your neighborhood connect to this box. From this box all of the different wires from your neighborhood run as one large cable to the local switch for your phone company, where the sound is digitally concentrated.
- Your voice is usually converted into a digital sample in eight-bit resolution, or about 8,000 sample per second. The digital sample then runs through a fiber optic cable to the phone company's office, where it is either looped into your network for a local call, or sent through a long-distance line for a call outside of your network.
- The call is then sent from the phone company office through the same process, through the wires, and to the person receiving your phone call. However, instead of the signal going from the microphone, it will be received into the speaker on the handset of the telephone. All of this happens within seconds.
