Digital Phone

Public Switched Telephone Network (PSTN) based on the relationship directly between the sender with the receiver must use copper wires, fiber optic, satellite, fixed wireless, and mobile wireless circuit.Use The network involves the basic components of the telephone, network access, central office (CO), trunks and special circuits, and customer premise equipment (CPE). Development of the PSTN as a digital telephone system has improved kalitas capacity of their networks and making it possible to use several channels of communication in a medium of exchange. Source : http://www.scribd.com