ATM when referring to computers is a dedicated, connection switching technology that organizes digital data into 53-byte(69)units and transmits them over a physical(70)using digital signal technology. ATM is capable oftransniitfing at speeds of 155 or 622 MBit/s and faster.

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In the following essay, each blank has four choices. Choose the best answer and write-down on the answer sheet.

 Microwave communication uses high-frequency(71)waves that travel in straightlines through the air. Because the waves cannot(72)with the curvature of the earth, they can be(73)only over short distance. Thus, microwave is a good(74)for sending data between buildings in a city or on a large college campus. For longer distances, the waves must be relayed by means of "dishes" or(75). These can be installed on towers, highbuildings, and mountain tops.

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