Technology Behind The Telephone

Society thrives because humans communicate, and the telephone allows us to do so quickly and efficiently. This device bridges gaps in distance, essentially connecting people around the world in just a single tap. It is hard to imagine living in a world without this level of convenience but that is exactly what our ancestors had to contend with. Face-to-face communication used to be the norm. After a while, humans learned to write and sent letters to convey messages. It got the job done but it was slow and unreliable. Eventually, people invented the telegram which was much faster. It was after the invention of the telephone, however, when things really began to change.

Early Development

The concept is simple and can be explained in any science workshop. Human voice produces sound waves. Telephones capture those waves and turn them into electrical signals. These are sent over a line or across stations to the recipient's own phone, with the device converting the signals back to sound using speakers. The most basic illustration uses cans connection via taut string. If a person talks to one can, the person on the other end should be able to hear the message because sound travels through this string. However, the signal will degrade over long distances.

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This problem was resolved by using increasingly complex electrical circuits. The signal got stronger while the noise was minimized. First they used to send the signals through copper lines. You pick up a phone and talk to a switchboard operator who routed your call to the right place. After a while, engineers developed phone systems where users could input the number they wish to reach to get a direct connection. Networks became more efficient at handling the volume of calls and improving the quality of the connections. As for the devices, rotary dials were eventually replaced by touch-tone signaling. 

Enter the Mobile Revolution

Although phones using landlines were fairly reliable, they were severely limited by the need to have physical connections. They could not be used in remote areas where it was not feasible to lay down wires across vast distances to service relatively few users. The devices were also bulky and heavy. Mobile phones ushered in a new revolution in communications thanks to their wireless connectivity and portability. The first ones were two-way radios used mostly by the police and cab drivers. Bell Labs started developing cell transmissions for mobile communications in the 1940s but it was not until the 1970s when the first cellular phone went public. 

Since then, phones just got smaller, lighter, and slimmer. They also evolved from being purely voice-based to being capable of text messages and data transmission. These days, we use phones to surf the Internet as well thanks to the increasing speed of cellular networks with each generation. We send email and chat with friends. We stream music and movies. We can even take photos, make payments, shop for products, navigate vehicles, send files, play games, and use a wide variety of applications. In the future, we may have wearable phones with long-term batteries capable of holographic reproduction and whole-house control.