Unit 5: Data Communication - Practice Quiz

1 What does the abbreviation LAN stand for?

2 Which type of network typically covers the smallest geographical area?

3 The largest global network of interconnected networks is called the:

4 What does WAN stand for?

5 A network that covers a city or a large campus area is best described as a:

6 A digital signal is best described as one that uses:

7 An analog signal is characterized by:

8 Which of the following is an example of analog data in everyday life?

9 Computers internally process and store data primarily in which form?

10 In digital transmission, data is commonly represented using which number system?

11 What is the primary function of a modem?

12 The word modem is formed from which two terms?

13 Standard telephone lines were originally designed to carry which type of signal?

14 A modem is required because a computer's digital signals cannot directly travel over:

15 The speed of a modem is commonly measured in:

16 What does DSL stand for?

17 Compared to a standard dial-up modem connection, a digital connection like DSL is generally:

18 Which of the following is a type of high-speed digital data connection?

19 Which technology is commonly used to connect devices to a wireless local network?

20 Which short-range wireless technology is typically used to connect a phone to a headset?

21 A company connects computers across three floors of a single building so employees can share a printer and files. Which type of network best describes this setup?

22 A multinational firm links its offices in New York, London, and Tokyo into one connected network. Which network type provides this global reach?

23 Which statement correctly compares a LAN with a WAN?

24 A signal that varies continuously and can take on infinitely many values within a range is best described as which kind of signal?

25 Why is digital transmission generally more resistant to noise than analog transmission over long distances?

26 Converting a continuous analog voice signal into a stream of 0s and 1s for transmission is an example of which process?

27 A digital signal is sent through a medium designed to carry analog waves, such as a traditional telephone line. What must happen first?

28 What does the term "modem" stand for, reflecting its two core functions?

29 At the receiving computer, what specific task does the modem perform on the incoming signal from the phone line?

30 A user with a standard dial-up modem cannot make voice phone calls while connected to the internet. What is the main reason?

31 A traditional dial-up modem is limited to roughly 56 Kbps. Which factor most directly limits this maximum speed?

32 If a modem transfers data at 48 Kbps, approximately how long will it take to download a file of 6 kilobytes (assume 8 bits per byte)?

33 A home user replaces dial-up with DSL and can now browse the web while talking on the phone at the same time. Why is this possible with DSL?

34 Which of the following is a genuine advantage of a leased digital line such as a T1 over a standard dial-up connection?

35 A business needs consistent upload and download speeds for video conferencing between two branches. Which connection characteristic is most important here?

36 Compared with copper-based DSL, why does fiber-optic digital connection typically support much higher data rates?

37 A student connects a laptop to the internet at a coffee shop using Wi-Fi. Which technology enables this local wireless connection?

38 A user wants to wirelessly connect a headset to a phone over a very short range with low power use. Which technology is most appropriate?

39 Which of the following is a realistic limitation of wireless networks compared with wired networks?

40 A traveler in a remote area with no cell towers or landlines needs internet access. Which wireless option is most suitable?

41 A channel has a bandwidth of Hz and a signal-to-noise ratio of dB. Using the Shannon capacity formula, the maximum theoretical data rate is closest to:

42 A noiseless channel has a bandwidth of Hz. Using Nyquist's theorem, what is the maximum data rate if each signal element encodes bits (16 levels)?

43 A modem operates at a baud rate of and achieves a bit rate of bps. How many bits per signal element are encoded, and what modulation scheme fits?

44 Standard telephone (POTS) local loops limit usable voice-band bandwidth to roughly – Hz. Why can V.90 modems reach kbps downstream but only kbps upstream?

45 A T1 line carries voice channels, each sampled at samples/s with bits per sample, plus framing bit per frame. What is its total data rate?

46 In ADSL, why is the upstream rate typically far lower than the downstream rate on the same copper pair?

47 Two Wi-Fi stations cannot hear each other but both can reach the same access point, causing collisions at the AP. Which mechanism specifically addresses this hidden node problem?

48 Why does IEEE 802.11 use CSMA/CA rather than CSMA/CD (as in wired Ethernet)?

49 A signal is sampled at exactly the Nyquist rate but the reconstruction shows a lower-frequency signal that wasn't in the original. What most likely occurred?

50 Ordering networks by increasing typical geographic scope, which sequence is correct?

51 A file of MB is sent across a link with bandwidth Mbps and a one-way propagation delay of ms. Ignoring processing/queuing, the approximate time from start of transmission to full receipt is:

52 A cellular provider reuses the same frequency in cells that are geographically separated. What is the primary limiting factor on how small the reuse distance can be?

53 A modem's connection negotiates down from kbps to kbps on a noisy line. Which combined explanation best fits modem adaptive behavior?

54 An ISDN Basic Rate Interface (BRI) provides 2B+D channels ( kbps bearer kbps signaling). If both B channels are bonded for data, the usable data throughput is:

55 In PCM digitization of a voice signal band-limited to kHz using -bit quantization, what is the resulting bit rate, and which parameter most directly controls quantization noise?

56 Compared to infrared, why do radio-frequency wireless technologies like Bluetooth and Wi-Fi dominate indoor networking?

57 A geostationary satellite link has a one-way propagation delay of about ms. For an interactive request-response (round trip) application, the minimum inherent latency contributed by propagation alone is approximately:

58 Why can DSL and voice telephone service coexist on the same copper pair simultaneously, while a traditional dial-up modem cannot share the line with a phone call?

59 A modem uses 8-PSK (8 phase states) at a symbol rate of baud. What is its raw bit rate, and what happens if it upgrades to 64-QAM at the same baud rate?

60 A long-distance link carries a signal that attenuates over distance. Which statement best contrasts how repeaters vs. amplifiers affect digital and analog transmission quality?