History of the telephone
The history of the telephone began with Alexander Graham Bell in 1876, the year he tested the electromagnetic telephone he invented for the first time outside of his laboratory in Boston over a distance of 8.5 km. However, even before he did so, Philipp Reiss had already sent speech through electrical signals in 1860. Still, it wasn't until the invention of Bell's simple telephone that this technology made its break-through and became practically relevant. In this context, one also shouldn't forget all of Bell's fellow scientists, who investigated the possibility of transmitting messages and electricity long before he did and whose work was essential as a foundation for Bell's telephone, such as Samuel Finley Morse with his Morse device, Benjamin Franklin with his lightning rod, Georg Simon Ohm with his Ohm's law and many others.
This was the initial spark for the unrivalled success of the telephone all around the world: The first manually-operated local networks already appeared in Germany in 1881. Soon after the invention of the predecessor of the dial plate by Almon Brown Strowger in 1889, automatic call transfers became possible. The changeover to automatic call transfers in Germany was initiated in 1908 and was only completed in 1972. The first connection between London and New York took place in 1928, straight across the Atlantic. Soon thereafter, connections were also possible between Germany and the New World, even if it was only from a few larger cities. In 1910, there were already approx. 1 million subscribers in Germany. Today, there are approx. 55 million subscriber lines in Germany, in comparison to approx. 270 million in China and approx. 200 million in the US. Thus, the telephone rapidly turned from a luxury item reserved for high society into a commodity available to everyone, that we could no longer without in our modern world.
And the evolution continues: Since the end of the 1980's, the line telephone network has become increasingly digitalized, especially for telephone and data traffic between two switching centers, but also on the "last mile" since the introduction of ISDN starting in 1989. From that time on, analogue voice signals are converted into digital data at the latest by the first switching centers, transferred in this form to the target switching centre, and then converted back to an analogue voice signal if necessary. And this trend will continue, since digital information in combination with packet switching networks offers an unbeatable advantage: Contrary to the classic circuit switching networks, the line is only busy when there actually is information to be transmitted. Also, the individual data packets may take any number of different paths through the communication network, depending on loads on the lines, on its way to the receiver, which grants the telecommunication companies a more flexible use of their infrastructure. If the internet protocol TCP/IP or the internet itself is used as a transmitting medium, one refers to 'Voice over IP' (VoIP). This type of solution is becoming very popular, as one can make calls anywhere in the world at local rates or even for free. Of course, this only applies if one already has a broadband internet connection with a flat rate, since the transmission of the voice packets takes place through the internet at no extra cost. If the person you are talking to is also using VoIP, there are no additional costs, otherwise the call has to be connected from the internet to the classic telephone network and back, preferably within the local loop of the receiving party. So now, for the first time, internet providers can compete with the fixed line providers.