For a phone to function properly, a duplex coil and frequency generator/touch-tone keypad are needed. With a landline phone, two copper wires run from a box at the road to a box in the house. According to How Stuff Works, the way telephones work has not changed in nearly a century. In the simplest telephones, there are only three small parts: a hook switch, a speaker and a microphone.
Telephones change a person's voice into electric signals, and a receiver changes the signals back into a voice, according to the Telecommunications History Group. Each phone jack in the house is connected to the two copper wires. A large cable with about 100 or more copper pairs runs along the road. This cable usually goes to the phone company's switch. Every person's voice is sent down a single wire to the phone company's office. The phone line connects to a line card at the switch so a dial tone is heard. A voice can be transmitted by fiber optics, satellite or microwave towers. Computers and air help transmit phone calls unlike wires and operators from decades ago; however, if an older phone was hooked up to a wall with a phone jack, it would still operate.