An old-style telephone, commonly referred to as a landline telephone, operates over long distances through a wired network rather than relying on sound waves traveling through the air. These telephones use physical wires to establish a connection between the two endpoints, enabling the transmission of electrical signals.
Here's a brief overview of how a landline telephone works:
Analog voice signals: When you speak into the microphone of a landline telephone, your voice is converted into analog electrical signals. These signals represent the variations in air pressure caused by your voice.
Electrical signals: The analog voice signals are transmitted as electrical signals through a pair of copper wires, known as a twisted pair. These wires form a physical connection between your telephone and the telephone exchange, which is a central switching station.
Telephone exchange: At the telephone exchange, the electrical signals from your telephone are received and routed to the destination telephone. The exchange acts as a central hub that connects multiple telephones within a local area or across long distances.
Connection establishment: When you dial a phone number, the electrical signals representing the dialed digits are sent to the telephone exchange. The exchange interprets the dialed number and establishes a connection with the destination telephone.
Signal transmission: Once the connection is established, the exchange sends the electrical signals representing your voice to the destination telephone over the appropriate wire pair. Simultaneously, the electrical signals from the other person's telephone are transmitted back to your telephone.
Receiving and conversion: The destination telephone receives the electrical signals and converts them back into analog audio signals. These analog signals are then amplified and delivered to the speaker of the receiving telephone, where they are heard as sound waves.
Throughout this process, the landline telephone relies on physical wires to transmit the electrical signals. The wires provide a dedicated, reliable pathway for communication, ensuring minimal interference and maintaining the integrity of the signal over long distances.
It's worth noting that older landline telephones were typically limited to connecting within a local area or region due to the infrastructure of wired networks. For long-distance communication, specialized equipment such as trunk lines and satellite links were used to connect different telephone exchanges and enable communication across greater distances.