Red vintage telephone isolated on white background.
| Photo Credit: Krittiraj Adchasai
The secret lay far away from your home. Unlike today’s smartphones, traditional landline phones did not depend on the electricity coming into your house. Instead, they drew power through the same copper wires that carried your voice. These wires were connected to a telephone exchange, a central hub that linked thousands of telephones together.The exchange constantly supplied a small amount of direct current (DC) electricity, usually around 48 volts, through the telephone lines. A traditional landline phone needed very little power, just enough to carry your voice and ring when someone called. Because the electricity came from the exchange rather than your home’s electrical supply, the phone continued to work even if your neighbourhood lost power.When you spoke into the handset, a small microphone converted your voice into electrical signals. These signals travelled through the copper telephone lines to the exchange, which routed them to the other person’s phone. There, a speaker converted the signals back into sound.In other words, while your lights, television and refrigerator stopped working during a blackout, the telephone line still carried both your conversation and the electricity needed to keep the phone alive. That clever design made landlines one of the most reliable ways to stay connected during emergencies.What is a telephone exchange?Think of a telephone exchange as the brain of the landline network. It is a central building where thousands of telephone lines from homes, offices and businesses come together. Whenever you dialled a number, the exchange recognised where the call needed to go and connected your phone line to the other person’s. In the early days, these connections were made manually by operators using switchboards. Later, automatic electronic systems took over, allowing calls to be connected within seconds.But the exchange did more than just connect calls. It also supplied a steady stream of electricity through the copper telephone lines. Since every landline was linked directly to the exchange, each phone received the small amount of power it needed to function. This clever setup meant that even if the electricity in your home went out, the exchange could keep your landline running.
