Telephone, Teletype, Telex, and Facsimile Transmission

The telephone network also uses both wireline and wireless methods to 1(deliver, bring, carry) voice communications between people, and data communications between computers and people or other computers. The part of the telephone network that currently serves individual residences and many businesses operates in an analog mode, uses copper wires, and relays electronic 2(alarm, signals, signs) that are continuous, such as the human voice. Digital transmission via fiber-optic cables is now used in some sections of the telephone network that send large amounts of 3(calls, rings, bells) over long distances. However, since the rest of the telephone system is still analog, these digital signals must be converted back to analog before they 4(come, reach, achieve) users. The telephone network is stable and reliable, because it uses 5(his, its, it) own wire system that is powered by low-voltage direct current from the telephone company. Telephone networks modulate 6(voice, music, sound) communications over these wires. A 7(difficult, hard, complex) system of network switches maintains the telephone links between callers. Telephone networks also use microwave relay stations to send calls from place to place on the 8(land, ground, earth). Satellites are used by telephone networks to transmit telephone calls 9(along, through, across) countries and oceans.