The idea was revolutionized in the 1920s, as more and more people purchased telephones and used them to communicate news, ideas, and personal information.
[1] During the 1990s, it was further revolutionized by the advent of computers and other sophisticated communication devices, and with the use of dial-up internet.
[2] There are a number of different types of telephone network: Public telephone operators (PTOs) own and build networks of the first two types and provide services to the public under license from the national government.
Virtual Network Operators (VNOs) lease capacity wholesale from the PTOs and sell on telephony service to the public directly.
This article related to telecommunications is a stub.