Do I Know This Already Quiz

The purpose of the "Do I Know This Already?" quiz is to help you decide whether you really need to read the entire chapter. If you already intend to read the entire chapter, you do not necessarily need to answer these questions now.

The 15-question quiz, derived from the major sections in the "Foundation Topics" portion of the chapter, helps you determine how to spend your limited study time.

Table 15-1 outlines the major topics discussed in this chapter and the "Do I Know This Already?" quiz questions that correspond to those topics.

Table 15-1 "Do I Know This Already?" Foundation Topics Section-to-Question Mapping

Foundations Topics Section

Questions Covered in This Section

Perspectives on the PSTN

1—2

Analog Modems

3—4

ISDN

5—7

DSL

8—10

Cable Modems

11—12

Comparisons of Remote Access Technologies

13—15

CAUTION The goal of self-assessment is to gauge your mastery of the topics in this chapter. If you do not know the answer to a question or are only partially sure of the answer, you should mark this question wrong for purposes of the self-assessment. Giving yourself credit for an answer that you correctly guess skews your self-assessment results and might provide you with a false sense of security.

1. Which of the following acronyms identifies a voice codec used to encode analog voice signals into a 64-kbps digital data stream?

a.

PSTN

b.

MCNS

c.

ADSL

d.

PCM

e.

AS-CELP

2. How many DS0 channels are in a DS1 in the United States?

a.

1

b.

2

c.

8

d.

16

e.

24

f.

28

g.

32

3. Which of the following best describes the function of demodulation by a modem?

a. Encoding an incoming analog signal as a digital signal b. Decoding an incoming digital signal into an analog signal c. Encoding a set of binary digits as an analog electrical signal d. Decoding an incoming analog electrical signal into a set of binary digits e. Encoding a set of binary digits as a digital electrical signal f. Decoding an incoming digital electrical signal into a set of binary digits

4. Which of the following modem standards do not support 56-kbps speeds downstream?

a.

V.22

b.

V.22bis

c.

V.42

d.

V.90

e.

V.92

f.

V.32

g.

V.32bis

h.

V.34

5. Which of the following terms best describes features of an ISDN PRI in Europe?

6. Imagine that you plug an analog phone into an ISDN modem and call a friend at her house, where she uses an analog phone using plain-old telephone service (POTS). At which of the following points in a network will a voice codec be used?

a. Your friend's telephone b. The phone switch into which your friend's local line is connected c. The phone switch into which your ISDN BRI line is connected d. Your ISDN modem e. Your telephone

7. What does the letter B stand for in the ISDN term B channel?

a. Bearer b. Broadband c. Binary d. Best

8. Which of the following DSL standards has a limit of 18,000 feet for the length of the local loop?

a.

IDSL

b.

DSL

c.

ADSL

d.

VDSL

e.

HDSL

9. Imagine a local phone line from a house to a local telco CO. When the customer at that house requests DSL service, what type of device does the telco move the CO end of the local line to?

a.

DSLAM

b.

DSL router

c.

DSL modem

d.

Class 5 switch

e.

Voice switch

f.

Head end

10. Which of the following protocols are used by DSL modem and routers for data link layer functions?

d. IEEE 802.1Q

e. MCNS MAC

11. Which of the following protocols is used by cable modems for data link layer functions?

d. IEEE 802.1Q

e. MCNS MAC

12. Which of the following protocols are used by a cable modem for the upstream data?

d. QAM-256

e. QPSK

13. Which of the following remote access technologies uses ATM, Ethernet, and PPP as datalink protocols?

a. Analog modems b. ISDN

d. Cable modems

14. Which of the following remote access technologies support specifications that allow both symmetric speeds and asymmetric speeds?

a. Analog modems b. ISDN

d. Cable modems

15. Which of the following remote access technologies, when used to connect to an ISP, is considered to be an "always on" service?

a. Analog modems b. ISDN

d. Cable modems

The answers to the "Do I Know This Already?" quiz are found in Appendix A, "Answers to the 'Do I Know This Already?' Quizzes and Q&A Sections." The suggested choices for your next step are as follows:

■ 12 or less overall score—Read the entire chapter. This includes the "Foundation Topics" and "Foundation Summary" sections and the Q&A section.

■ 13-15 overall score—If you want more review on these topics, skip to the "Foundation Summary" section and then go to the Q&A section. Otherwise, move to the next chapter.

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