Ιn the mid-1970s, the digital revolution began, the world moved from mechanical-electrical technology to digital. We are slowly moving into the era of information technology and communications that will forever change the lives of the inhabitants of this planet. It was inevitable that the design and construction of telephones would be affected. No more analog circuits…now all the components are mounted on a single board, with many of them the size of a lentil. The carbon capsules of the earphone and microphone are replaced by capacitors. The bell circuit is also replaced by an electronic one. Devices are becoming much lighter. However, the main component that changes is the selection disc, which is replaced by the keyboard, to which buttons are constantly being added, preparing for the digital conveniences that will come in the coming years. Several years later, screens were installed that displayed various information.