Taylor Made: Come here, Mr. Watson

Samuel Morse developed the commercial telegraph in the 1830s. He and his assistant, Alfred Vail, created the accompanying communication system Morse code to send messages through the telegraph. Morse code translated each letter of our alphabet into combinations of short and long pulses. The “dots” (short pulses) and “dashes” (long pulses) could be electrically transmitted along long distance wires to receiving machines.

The telegraph paved the way for another invention that used electrical pulses to send messages, but this time with more complex audio. Created by Alexander Graham Bell in 1876, it was called the telephone.

Early telephones acted as transducers, changing sound energy into electrical energy and back again. When a person spoke into the telephone’s diaphragm, they transmitted acoustic waves with accompanying sound pressure.  Behind the diagram was a collection of tiny carbon grains, through which low voltage current passed as part of the live circuit made by the sending and receiving telephones, the power source provided by the telephone company, and the connecting wires.

The carbon grains had minute spaces among them while at rest. When waves propagated through the diaphragm, the sound pressure would act on the grains and cause them to compress. Stronger sound pressure caused more compression, allowing the current to travel faster through smaller gaps among the grains. Softer pressure caused less compression, allowing less current to pass through in the same amount of time. In this way, each distinct wave with its corresponding pressure would create an electrical pulse that traveled down the wire.

The pulse vibrated a second diaphragm through use of an electromagnet (iron with live wire coiled around it) when they reached the receiving telephone, thus reproducing the sound for the listener.   

Today’s cellphones operate in a very different way. Circuitry converts the acoustic waves into electrical signals that are translated into strings of numbers. The strings travel via radio wave to a cell tower, where they are routed to a second tower nearest the receiving phone. The receiving tower sends them to the phone itself, where they are converted back into acoustic frequencies and played through a speaker.

As with many inventions, Bell’s creation was widely regarded as a joke at its debut. But by the time he died in 1922, telephones numbered in the millions and were already used all over the world.  

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