This is an undated photograph of the first telephone, patented in 1876 by inventor Alexander Graham Bell.

“The horse does not eat cucumber salad” were the first words which the German teacher and physicist Johann Philipp Reis spoke into his telephone in 1861.

He chose the curious sentence to make sure that it would be understood word for word without the listener being able to guess the meaning of the sentence from the gist. His telephonic device was able to convert sounds into an electrical current and to reproduce them in another place. But the inventor was evidently too far ahead of his time: his invention was considered sheer lunacy.

In 1872, over ten years later, the Scottish-born inventor and teacher Alexander Graham Bell built an electromagnetic telephone in Boston with which speech could be transmitted over large distances. His work with deaf people had inspired him to investigate the physical creation of sound.

On 10th March 1876, Bell presented his Box Telephone to the public on a test line of around eight kilometres. The basic principle upon which the equipment operated still applies to today’s telephones. A thin steel membrane absorbs the sound waves of the words spoken and vibrates in a way which corresponds exactly to the modulation of these waves. The membrane converts the pattern of the sound waves into analogous vibrations of a current, whose intensity, in turn, fluctuates according to the original modulation. In the receiver, the electrical impulses are picked up by an electromagnet which causes a membrane to vibrate. It then emits sound waves which the person at the other end receives via the ear.

In 1877, Thomas Alva Edison succeeded in enabling telephone calls to be made over large distances by creating stronger electrical impulses. Moreover, he also developed a separate microphone and loudspeaker. If the receiver was hung upon the hook provided, the connection was cut off. From then on, things really took off: the invention of the carbon microphone in 1878 improved transmission quality significantly.

In 1884, the first long-distance line was laid from New York to Boston and by 1900 there were automatic telephone switchboards almost everywhere in the world.

In 1956, the transatlantic underwater cable for telephone communication between Scotland and Newfoundland was laid and 1972 saw the invention of the video telephone.

Always and everywhere – wireless, limitless communication  

The telephone became portable on 20th February 1942. On this day, the American, Donald M. Mitchell, applied for a patent for his "Portable Radio Transmitting and Receiving" mobile telephone. The device transmitted using short waves, had a limited range and weighed no less than 2.5 kilograms.

Another 35 years were to pass before mobile phones could be used by ordinary members of the public. It was not until 1983 that Motorola presented the first commercial mobile telephone in the world, the "Dyna TAC 8000X".