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(63)

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

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In(66)the strength of the carrier signal is varied to represent binary 1 or 0.(67)is a system that can map a name to an address and conversely an address to an name.(68)is a three -way handshaking authentication protocol that it's packets are encapsulated in the point - to -point protocol.(69)is an approach that enables an ATM Switch to behave like a LAN switch.(70)is an guided media which is made of glass or plastic and transmits signals in the form. of light.