Bài tập tiếng anh chuyên ngành điện tử viễn thông

carried out by the ubiquitous telephone network. Again, a modem was required to integrate the 
service into analog telephone network. 
By this time the worldwide telephone network was in place and pervasive. Using that 
network turned out to be the most cost-effective method to communicate other information (i.e., 
other than speech telephony) from point X to point Y. Dial-up telephone connections provided 
one way of achieving switched service to transport that "other" information, whether point-to-
point or multipoint. 
 41
Point-to-point modal 
Point- to-multipoint modal 
Digital telephony began to take hold after the development of the transistor in 1948. Solid-
state circuitry, particularly in LSI, made pulse-code modulation (PCM) transmission and later 
PCM switching cost-effective. 
A. Match the two columns. 
1. nineteen 
century 
2. In 1950s 
3. In 1948 
4. 30 years 
5. 4-Khz 
a. The present analog telecommunications network is based on that 
voice channel. 
b. The only two services were telegraph and telephone. 
c. Computer-related data began to emerge. 
d. The development of the transistor 
e. Telegraph predated the telephone. 
B. Answer the questions. 
1. What services evolved separately and distinctly in the nineteen century? 
..................................................................................................................................................... 
2. What was the next service that was integrated rapidly into the telephone network? 
..................................................................................................................................................... 
3. What did facsimile require to make it compatible with analog telephony? 
..................................................................................................................................................... 
4. What did computer-related data require? 
..................................................................................................................................................... 
5. What made PCM transmission and PCM switching cost-effective? 
 42
..................................................................................................................................................... 
Exercise 6. A. Read the text then match the numbers with the explanations. 
MANAGEMENT FOR THE RIGHT DEVELOPMENT TREND 
The event of inaugurating the Internet in Vietnam 2 years ago was warmly welcome. Until 
now, the number of Internet subscribers has continuously increased. In June, 1999 the 
development speed was 30% in comparison with the beginning of 1999, monthly 1,500 
subscribers added to the network on average. At the moment, there are 1 IAP, 5 ISPs, 14 
private networks, 16 ICPs; and over 40,000 users, excluding 15,000 users of 14 private 
networks. It is estimated that by the year 2000, Vietnam will have more than 100,000 Internet 
subscribers. This places Vietnam regulators in a very heavy duty of how to make Vietnam 
Internet develop on the right trend. 
Mr. Chu Tuan Nha, Minister of Science Technology and Environment, Director of 
Vietnam Internet National Coordination Board, confirmed: the cooperation of ministries, sectors 
under the framework of the Internet National Coordination Board has brought obvious 
effectiveness to the development of Vietnam Internet. Although it is a new service, necessary 
document systems are almost enough for ensuring the right development of Vietnam Internet. 
After the promulgation the 21/ CP Decree concerning the temporary regulations on 
establishment, management and using Internet in Vietnam; the 136/ TTg Decision relating to the 
establishment of the National Coordination Board, the Board quickly published a system of 10 
legal documents directly related to guidance on implementing the 21/ CP Decree. These legal 
documents hold a very important role in creating basic legal environment for organising, 
managing and exploiting Internet services, which were firstly introduced in Vietnam. So that, fair 
competition between services providers was created. 
Under the estimation of the Board, after 2 years in operation, all licensed operators (IAP, 
ISP and ICP) tried their best to comply with the State’s regulations. Information provided on 
Internet has transmitted official information of Vietnam worldwide under the forms of electronic 
newspapers, but the diversification of information is still limited and repeated. 
The safety of transmission and information on line has been paid much attention for both 
coming and going resources, especially the going one. However, the information management, 
especially the coming one, has met some difficulties because of limited ability of the firewall, not 
strong enough to control information with bad content. Although IAP, ISPs and ICPs for private 
networks were advised to set up security systems at national gateways and servers at their private 
gateways, the limitation of finance resource is the main reason for the above mentioned fact. 
Otherwise, some illegal forms of using the Internet occurred, causing difficulties for ensure the 
security on line. 
In the coming years, Vietnam economy continues its development together with the 
expansion in cooperation with regional and international organisations. Activities on line, such as: 
e-commerce, information exchange, etc, will be increased. 
 43
1. 30% 
2. 1,500 
3. 1 
4. 14 
5. 10 
6. 100,000 
7. 136/ TTg 
8. 40,000 
9. 21/ CP 
a. number of IAP at the moment 
b. Decision relating to the establishment of the National 
Coordination Board 
c. number of Internet subscribers Vietnam will have in 2000 
d. monthly subscribers added to the network on average 
e. legal documents directly related to guidance on implementing 
the 21/ CP Decree 
f. the development speed in June, 1999 compared with the 
beginning of 1999 
g. number of private networks at the moment 
h. Decree concerning the temporary regulations on establishment, 
management and using Internet in Vietnam 
i. number of users at the moment 
j. Decision relating to the establishment of the National 
Coordination Board 
B. Translate the text into Vietnamese. 
Exercise 7. Translate into English. 
Để đáp ứng yêu cầu quản lý Internet Việt nam cần phải tiến hành 6 nhiệm vụ chính sau: 
• Thiết lập các văn bản hoàn chỉnh cho việc phát triển Internet. 
• Tiếp tục thiết lập một môi trường hợp pháp và tham gia tích cực trong việc phát triển 
Internet. 
• Đẩy mạnh việc giám sát và đầu tư các hoạt động. 
• Hỗ trợ các hoạt động của các doanh nghiệp về dịch vụ khách hàng, cho phép các kế hoạch 
thử nghiệm các dịch vụ mới, xem xét lại phí truy nhập Internet. 
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 44
• Nghiên cứu và áp dụng các dịch vụ mới dựa trên cơ sở Internet như thương mại điện tử. 
• Đẩy mạnh hợp tác quốc tế; phát triển nghiên cứu công nghệ về Internet nhằm nhanh 
chóng áp dụng và khai thác những công nghệ mới ở Việt nam. 
Exercise 8. Fill in the blanks with suitable form of the words. 
Computer telephony integration (CTI) is a term to which many are becoming..................... 
(1. accustom). It encompasses an entire industry, devoted to the closer ................................ (2. 
integrate) of telephony systems with computer-control devices, as well as an ever-expanding 
range of ................................... (3. apply). At the forefront of this industry are innovative products, 
built using hardware able to terminate ................................ (4. digit) telephony tier (T1) and E1 
(T1 European equivalent) trunk interfaces, fax and voice .............................. (5. process) 
resources, voice-over-IP (VoIP) technology, and other standard peripheral ................................(6. 
device). 
Typically, these operate in industrialized chassis housings and act as ............................... 
(7. switch), voice-mail servers, automatic call distributors (ACDs), and nearly any other kind of 
telco-equipment imaginable. The CTI revolution has led to a ...................................(8. generate) of 
such equipment, upsetting traditional motions of how telephony networks should be built. 
Exercise 9. Read the following text carefully. 
TWISTED-PAIR SOLUTIONS FOR INTERNET ACCESS 
There are three major categories of twisted-pair solutions that are being used for Internet 
access: 
* Voice band data (VBD) modems 
* ISDN digital subscriber line (DSL) 
* Other DSL approaches (xDSL) 
VBD modems are well known and understood by residential and small-business users. 
They operate be using the voice-frequency band of the twisted-pair facility to transmit data, using 
frequency shift keying (FSK) or quadrate amplitude modulation (QAM) transmission techniques. 
Symmetric rates exist up to 33.6 Kbps, with the majority running at 14.4 and 28.8 Kbps and 
return-path rate operating up to 33.6 Kbps. 
Integrated services figural network (ISDN) is a digital baseboard technology that operates 
with a 144-KBPS bidirectional payload rate using 2B1Q encoding scheme. The 144 Kbps rate is 
divided into two 64 Kbps (B) channels and one 16 Kbps 9d channel. The B channels can be used 
for two separate voice calls, two 64 Kbps data calls, a separate voice and data call, or a combined 
128 Kbps data call. The wire limit for ISDN is 18.000 feet of standard twisted pair. 
xDSL Technologies 
A variety of xDSL rates and technologies have been standardized, or are in the process of 
standardization, by American National Standards Institute (ANSI) and the Asymmetric Digital 
Subscriber Line (ADSL) Forum. The higher r