Chapter 08
TRUE/FALSE
1. Analog modems are used in preference to digital technologies, even where digital technologies are
widely available.
2. A digital modem does not modulate/demodulate signals.
3. Hardware flow control halts and resumes the movement of data by sending special characters.
4. Mac OS X uses the Network Connection tool for configuring modems and other network connections.
5. The Network and Sharing Center is used in Windows Vista and Windows 7 OSs to set up a dial-up
connection.
MULTIPLE CHOICE
1. Which of the following is NOT a component of an analog modem?
a.
UART
c.
data pump
b.
CSMA/CD
d.
controller
2. You are configuring an analog modem for a point-of-sale device and are deciding which modulation
protocol to choose. Which of the following is NOT one of your choices.
a.
V.44
c.
V.34
b.
V.90
d.
V.92
3. Which of the following is true about using software-based modems?
a.
they do not have a hardware UART
c.
the data pump is implemented as a
software algorithm
b.
they use more memory and CPU cycles
than hardware-based modems
d.
they cannot transfer data as fast as
hardware modems
4. You are researching the possibility of upgrading your analog modem to ISDN. Which of the
following is true about ISDN modems and connections?
a.
you can only connect one device to an
incoming line
c.
ISDN works only on fiber optic lines
b.
the BRI has a data rate of 1.544 Mbps
d.
you can have a voice and data connection
simultaneously
5. You are weighing the benefits of the major communications technologies. Your main concern is
having a high bandwidth connection to the Internet. Which of the following technologies provides the
highest bandwidth connections?
a.
ISDN PRI
c.
ADSL
b.
Cable modem
d.
SDSL
6. You have a laptop with a built-in analog modem. You are at a hotel and must connect to the company
network with the modem. The hotel phone system requires that you dial a 9 before the phone number.
You have found that it takes a second or two to get a dial-tone after you dial the 9. What command
should be used on the modem to dial the number: 928-555-1932?
a.
dt 9285551932
c.
atdt 9,9285551932
b.
dt 99285551932
d.
atdt 99285551932
7. When accessing the Internet through a wi-fi connection, which of the following is NOT a suggested
security measure you should follow?
a.
use MAC address filtering
c.
disable SSID display
b.
disallow all incoming packets
d.
enable the firewall
8. Which of the following is true about cable modem connections.
a.
DOCSIS 3.0 combines multiple channels
to increase speed
c.
DOCSIS 3.0 provides added speed but not
added security
b.
upstream data rates are always lower than
downstream data rates
d.
your connection to the Internet through the
cable provider is a dedicated line
9. While considering whether to use DSL for an Internet connection, which of the following is NOT a
valid consideration?
a.
DSL lines are dedicated to a single
customer
c.
DSL subscribers do not share the
bandwidth with other subscribers
b.
ADSL provides a faster downstream than
upstream data rate
d.
only a single user can access the Internet
through a DSL connection
10. Which of the following is NOT a component in a typical satellite Internet connection?
a.
satellite dish
c.
digital modem
b.
twisted-pair cable from dish to modem
d.
USB cable from modem to computer
11. You have been called to troubleshoot a satellite Internet connection. Based on your knowledge of
how satellite communications work, which of the following is NOT likely to be the cause of the
problem?
a.
severe rain storms
c.
excessively bright sunlight
b.
snow on the dish
d.
heavy satellite usage
12. You are analyzing a serial communication session. You are able to view each character as it is
transmitted and received. You suspect a problem with the software flow control. Which of the
following characters is involved in software flow control?
a.
Ctrl-S
c.
Ctrl-O
b.
Ctrl-F
d.
Ctrl-V
13. You are verifying a computer’s parity checking by analyzing the bits received through a serial
communication port. The system is set for even parity. Which of the following bit streams indicates
a parity error?
a.
100100110
c.
100000001
b.
110000101
d.
111000011
14. Which of the following standards is used my modems for error checking?
a.
v.92bis
c.
v.42
b.
v.90
d.
v.32bis
15. Data compression on modems is accomplished “on the fly” by using which of the following methods?
a.
PKZIP
c.
TAR-Z
b.
LZJH
d.
TIFF
16. In Unix/Linux, you refer to the first modem on the computer using which of the following?
a.
/dev/ttys0
c.
/dev/com0
b.
/dev/ttys1
d.
/dev/com1
17. You have arrived at a customer site who is having problems using a modem attached to his Linux
server. The GUI is not installed on the server. Which command can you use to verify and configure
the modem?
a.
Network Connection tool
c.
ln -s /dev/ttys1
b.
/dev/getty
d.
minicom
18. You have a Mac computer that you need to connect to the Internet. The only network connection
available on the computer is a Bluetooth adapter. You are in range of a wi-fi hotspot that you have
access to. What, if anything can you do to connect this computer to the Internet?
a.
Put the Bluetooth adapter in wi-fi mode
and connect to the wi-fi hotspot
c.
create a DUN using Network and Sharing
Center and connect to your Bluetooth
phone
b.
configure a Bluetooth DUN on the Mac to
use your Bluetooth phone’s Internet
connection
d.
connect to a DSL modem using Bluetooth
and use PPPoE to access the Internet
19. When connecting to an analog modem using Windows XP, which of the following is a possible port
name through which you communicate to the modem?
a.
COM2
c.
LPT1
b.
TTY0
d.
UART0
20. What protocol does a dial-up networking connection use to access the ISP for Internet
communications?
a.
ISDN
c.
PPP
b.
UART
d.
DOCSIS
COMPLETION
1. Computers store data as a series of 1s and 0s represented by the presence or absence of _________.
2. A desktop computer with a modem is called a ________ device because it prepares data to be
transmitted.
3. The _______ is a component of a modem that reads in one byte of data, adds a start and stop bit and
feeds the bits to the port.
4. ____________ uses digital communications over a communications line and has an aggregate data rate
of 144 Kbps or 1.544 Mbps
5. ___________ checking is a data verification process that ensures data integrity through a system of
data bit comparisons between the sending and receiving computer.
MATCHING
a.
flow control
f.
protocol
b.
cable modem
g.
ADSL
c.
synchronous communication
h.
Xon-Xoff
d.
data pump
i.
modem
e.
daemon
j.
asynchronous communication
1. a high speed technology that can use ordinary telephone lines for downstream transmissions speeds up
to 8 Mbps and upstream speeds up to 1 Mbps
2. the hardware or software portion of a modem that is responsible for
converting digital data into analog signals for transmission over a telephone line
3. a hardware or software feature in modems that lets a receiving modem
communicate to the sending modem that it needs more time to process previously sent data
4. an internal, automatically running program, usually in UNIX/Linux, that serves a particular function
such as routing e-mail to recipients
5. a hardware device that permits a computer to exchange digital data with another computer via an
analog telephone line or dedicated connection
6. communications that occur in discrete units in which the start of a unit is signaled by a start bit at the
front, and a stop bit at the back signals the end
of the unit
7. communications of continuous bursts or blocks of data controlled by a clock signal that starts each
burst or block of data
8. a software flow control protocol that permits a receiving modem to notify the
sending modem that its data buffers are full
9. an established guideline that specifies how networked data, including data sent over a telephone
network, is formatted into a transmission unit
10. a digital modem device designed for use with the cable TV system providing
high-speed data transfer.
SHORT ANSWER
1. Briefly describe what a modem does.
2. What task does the controller component in a modem perform?
3. Briefly describe the role of the UART in a modem.
4. What type of signal is embedded in the data of synchronous communication lines?
5. What is a winmodem and what is a disadvantage of using one?
6. What command would you send a Hayes compatible modem if you wanted the modem to ignore
incoming calls?
7. What are the two interfaces supported in ISDN and what are their respective data rates?
8. Name two enhancements of DOCSIS 3.0 over non-DOCSIS compliant cable modems?
9. What is the difference between ADSL and SDSL?
10. Describe how software flow control works.