1. The Internet is the largest repository of information which can provide very very large network resources. The network resources can be divided into ____________. C A. communication resources and computer resources B. servers resources and bridges resources C. facilities resources and information resources D. hardware resources and software resources 2. As more an more systems join the Internet, and as more and more forms of information can be converted to digital form, _______________ . A A. the amount of stuff available to Internet users continues to grow B. the Internet becomes very busy C. the number of Internet users becomes very large D. the information in Internet is shared by more people 3. Before you can use the Internet, you must ______________ . B A. understand the regulations of the Internet B. choose a way to move data between the Internet and your PC C. install a server D. study the concept of the communications 4. ______________ is a networked hypertext protocol and user interface. D A. Asynchronous serial interface B. E-mail C. Internet D. World wide web 5. Today thousands of networks and millions of computers ___________ the Internet. A A. are connected to B. connected to C. to connect D. connecting to 6. The NISDN cannot transport TV signals ____________ its limited bandwidth capabilities, so a special TV network is still ___________. C A. because, require B. with, to require C. due to, required D. within, requiring 7. Each network is only capable _____________ one specific service for ____________ it was intentionally designed. A A. of transporting, which B. transporting, one C. transport, where D. to transport, when 8.Computer data ___________ in the public domain by a packet switched data network __________ X.25 protocols. A A. are transported, based on B. transports, base on C. transported, based on D. to transport, base 9. When ___________ the future BISDN network, one must ___________ all possible existing and future services. B A. design, take B. designing, take into account 10. Today’s telecommunication networks are characterized ____________ . A A. by specialization B. by teleservices C. by analog transmission D. by digital transmission 11. Perhaps the biggest reason for the explosion of multimedia offerings is the enormous advance in_______________. B A. large-scale integrated circuits B. personal desk top computers C. optic fiber communications D. mobile communications 12. The first element associated with multimedia is perhaps the CD-ROM, now considered a mature technology. The CD-ROM is used_______________. D A. to store the amplitude value B. to transmit the characters C. to store the speech signal D. to store data representing visual imagery 13. A crucial element in the provision of multimedia is the use of compressed video. Without compression the amount of storage that would have to be provided by the CD-ROM would be____________. B A. very small B. immense C. very weak D. a little 14.The standards for moving pictures are set by _______________ as international standards. C A. CCTT B. ITU C. MPEG D. GSM 15. If we consider the business area of multimedia applications, _____________ and that information must come to the user in real time and therefore be processed in real time. C A. the data transmission is important B. the quality of the radio link essential C. the voice provision is concerned D. the provision of video is crucial 16.The telephone contains a transmitter and receiver for _______________ back and forth _____________ analog voice and analog electrical signals. B A. convert, in B. converting , between C. conversion, to D. converted, into 17. Each subscriber connects ______________ local loop to a switching center, ______________ as an end office. D A. to , calling B. with , known C. the , know D. via, known 18. The trunks are designed ______________ multiple voice-frequency circuits ______________ either FDM or synchronous TDM. D A. carry, use B. carried, used C. to carry, to use D. to carry, using 19. Although originally _______________ to service analog telephone subscribers , the telephone network handles substantial data traffic ______________ modem , and gradually being converted to a digital network . A A. implemented , via B. implementing , in C. to implement , within D. design, on 20. Designers have found it convenient _____________ these nodes into a hierarchy or tree topology , ______________ five classes of switching centers or nodes. C A. organization , consist B. organize , consisting C. to organize , consisting of D. organizing , to consist Generally speaking, how many separate operations is PCM dependent upon? (B) A. Two B. Three C. Four D. Five 22. Which of the following is the range of a voice channel? (A) A. 300Hz---3.4Khz B. 3KHz---3.4KHz C. 3400Hz---3KHz D. 800Hz---34KHz 23. Which sampling rate do the practical equipments normally utilize? (D) A. 800Hz B. 16KHz C. 32Khz D. 8KHz 24. Which of the following signifies the relationship of the true signal to the noise signal? C. A. repetition rate of the pulse B. time to amplitude value C. signal-to-noise ratio D. the amplitude of the sampled signal 25. What is codec short for? D A. 编码器 B. 解码器 C. 调制解调器 D. 编解码器 26. ISDN’s enormous importance is only gradually being ___________ . Years of work have been ____________ by the CCITT and the ISO. D A. understand, carry B. understanded, carried C. to be understood, to carry D. understood, carried out 27. The term ISDN was first defined within the CCITT in 1972. It referred to a network ___________ end-to-end digital connectivity __________ a range of services. A A. providing, for B. provision, to C. provided, with D. provide, into 28. Similarly, the introduction of voice encoding techniques ____________ pulse code modulation contributed ___________ the ISDN’s concept evolution . B A. usage, on B. using, to C. use, with D. used, so as to 29. In fact, ISDN __________ conceived a quarter of a century ago and is only now _________ to reach maturity. B A. is, begin B. was, beginning C. be, to begin D. will be, began 30. The enhanced quality is achieved when a signal is digitally encoded ___________ degradation ___________ the transmission medium. D A. overcome, to B. overcame, with C. overcoming, over D. to overcome, due to 31. 全球通信A A .global communication B. national communication C. international communication 32. 灵活性A A. flexibility B. active C. lively 33. 通信载体A A. communication carriers B. communicating carry C. communicated movement 34. 基本接入C A. basic access B. basic entrance C. base access 35. 语音编码A A. voice encoding B. sound encoding C. voice codes 36. As more routing function are implemented in the optical place, we need . A. A. more sophisticated intelligence to control and manage the network B. self-healing properties and fast restoration times C. direct access to the optical network D. live video coverage of a medical operation 37. Therefore, to handle various types of traffic, C. A. this in itself would be big enough challenge to meet B. this allow the OA to amplify more signals simultaneously C. today's network will gave to be progressively optimized D. the different types of traffic can be assigned to different wave- length, as required 38. Second, the development of gain equalization techniques has enabled a much flatter response and allow . B. A. much more exacting requirements for quality differentiation B. a number of these amplifier to be connected in series C. the majority of traffic in the near future D. our understanding of the properties of light 39. For this reason, the growth of various application, such as telephony, Internet, video transmission, computer communication and database access on the network. D. A. would not likely to imagine the communication network of today B. be only at the beginning of what is possible C. have already been demonstrated D. leads directly to an increase in the demand placed 40. The major advance that has led to the WDM revolution . C. A. can boost the power of all wavelength B. will be used to convey large amount of video information in the future C. has been the invention of OA D. is access to the optical network 41. An asynchronous serial data link is said to be character oriented, _______________. C. A. since the line is in an idle state B. because it has a duration of T seconds C. as information is transmitted in the form of groups of bits called characters D. since it consists of 2 to 4 control bits 42. When the transmitter wishes to send data, it first ______________. A A. places the line in a space level B. puts the line in a mark level C. sends a stop bit D. places a bit at logical 1 level 43. Then a single parity bit is calculated by the transmitter and ______________ C. A. compared with the received parity bit B. sent with the data bits C. sent after the data bits D. sent before the data bits 44. The falling edge of the start bit triggers the receiver’s local clock, which ___________ A A. samples each incoming bit at its nominal center B. constructs a new character C. indicates a transmission error D. monitors the line looking for a start bit 45. The most obvious disadvantage of asynchronous data transmission is _____________. C. A. the transmission error B. referred to as the mark level C. the need for a start, parity, and stop bit for each transmitted character D. the receiving timing 46. In fact, the asynchronous serial data link is _____________. B A. the era of teleprinter B. a very old form of data transmission system C. a CRT terminal D. a special means 47.At the receiving end of an asynchronous serial data link, the receiver continually monitors the line _____________ . C. A. waiting for the end of the start bit B. generating a clock C. looking for a start bit D. constructing a new character 48. For mobile the problem is far more complex, with the need to roam ___________ a need for complex networks and systems. Thus in mobile the question of standards is far more crucial to success ___________ fixed systems. B A. to create, in B. creating, than C. creation, that D. created, with 49. The broadcast mobile networks, ___________ in densely populated areas, could be ___________ by a very small number of simultaneous calls. C A. operation, jam B. operate, jam C. operating, jammed D. to operate, to jam 50. The use of digital radio transmission and the advanced handover algorithms between radio cells in GSM networks allows for better frequency usage __________ in analogue cellular systems, thus ___________ the number of subscribers that can be served. D A. that, creation B. which, create C. the, to create D. than, creating