In short, within 50 years of invention, the landline became an indispensable tool of communication in all parts of the world. It was the time of 1900 when there were reportedly more than 600,000 phones in operations. By 1905 there were more than 2.2 million phones in use. Later in 1910, the toll reached 5.8 million. Later, as the century reached to end, the number of telephone users exploded. Soon after that came the idea of digital cellular phones that exists massively around us, to this date.