Cabling the WAN 239
To connect an ADSL line to the ADSL port on a router, perform the following simple
steps:
Step 1 Connect the phone cable to the ADSL port on the router.
Step 2 Connect the other end of the phone cable to the external wall phone jack.
To connect a router for DSL service, you need a phone cable with RJ-11 connectors. DSL
works over standard telephone lines. It uses only two pins on the RJ-11 connector, as
shown in Table 4-8.
Routers and Cable Connections
Cable modems enable two-way, high-speed data transmissions using the same coaxial
lines that transmit cable television. Some cable service providers are promising data
speeds up to six and a half times that of T1 leased lines. With the demand for broad-
band services, cable modem connection is becoming more popular.
The Cisco uBR905 cable access router provides high-speed network access on the cable
television system to residential and Small Office, Home Office (SOHO) subscribers.
The uBR905 router has a coaxial cable (F-connector) interface that can be connected
to a cable system. Coaxial cable and an F connector are used to connect the router and
cable system. The coaxial cable can be either radio grade 59 (RG-59) or RG-6, although
RG-6 is recommended.
To connect the Cisco uBR905 cable access router to the cable system, follow these
steps:
Step 1 Verify that the router is not connected to power.
Step 2 Locate the RF coaxial cable coming from the coaxial cable CATV wall
outlet.
Table 4-8 Telephone Connector Pinouts (RJ-11)
Pin Signal
1 Unused
2 Unused
3 Transmit (Tx)
4 Receive (Rx)
5 Unused

6 Unused
NOTE
If you are connecting
non-DSL devices to a
phone line with DSL
service, you need to
install a filter to pre-
vent interference
between data and
voice services.
NOTE
RF coaxial cable con-
nects radio frequen-
cies to antennas. The
majority of cable TV
systems use coaxial
cable as their wiring
system. The main
trunk lines that
run from the cable
provider to a neigh-
borhood distribution
boxes might be fiber-
optic, but coaxial
cables are likely to be
used in runs between
the distribution boxes
and the end user.
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240 Chapter 4: Cable Testing and Cabling LANs and WANs

Step 3 Install a cable splitter/directional coupler, if needed, to separate signals
for TV and computer use. If necessary, also install a high-pass filter to
prevent interference between the TV and computer signals.
Step 4 Connect the coaxial cable to the F connector of the router, as shown in
Figure 4-51. Hand-tighten the connector, making sure that it is finger-tight,
and then give it a 1/6 turn with a wrench.
Figure 4-51 F Connector
Step 5 Make sure that all other coaxial cable connectors—all intermediate split-
ters, couplers, or ground blocks—are securely tightened from the distribu-
tion tap to the Cisco uBR905 router, following the instructions in Step 4.
Setting Up Console Connections
To initially configure your Cisco device, you need to provide a management connec-
tion directly to the device. For Cisco equipment, this management attachment is called
a console port. The console port enables you to monitor and configure a Cisco hub,
switch, or router.
The cable used between a terminal and a console port is a rollover cable with RJ-45
connectors, as illustrated in Figure 4-52.
Figure 4-52 Setting Up a Console Connection
C
AUTI
O
N
Do not overtighten
the connector; doing
so can break off the
connector. Use of a
torque wrench is
not recommended
because of the danger
of tightening the con-

nector more than
the recommended
1/6 turn after it is
finger-tight.
chpt_04.fm Page 240 Tuesday, May 27, 2003 9:01 AM
Cabling the WAN 241
The rollover cable, also known as a console cable, has a different pinout than the
straight-through or crossover RJ-45 cables used with Ethernet or the ISDN BRI. The
pinout for a rollover is as follows:
1 to 8
2 to 7
3 to 6
4 to 5
5 to 4
6 to 3
7 to 2
8 to 1
To set up a connection between your terminal and the Cisco console port, you must
perform the following steps:
Step 1 Cable the devices using a rollover cable. You likely need an RJ-45-to-DB-9
or an RJ-45-to-DB-25 adapter for your PC or terminal.
Step 2 Configure your terminal emulation application with the following com-
mon equipment (COM) port settings:
■ 9600 bps
■ 8 data bits
■ No parity
■ 1 stop bit
■ No flow control
Lab Activity Establishing a Console Connection to a Router or Switch
In this lab, you connect a PC to a router or a switch to establish a console

session and observe the user interface.
Lab Activity Troubleshooting Interconnected Devices
In this lab, you create a simplerouted WAN with two PCs, two switches (or
hubs), and two routers. You configure workstation IP addresses. You then
identify and correct networking problems related to cabling issues and work-
station IP addressing issues.
NOTE
The auxiliary (AUX)
port on the router is
used to provide remote
management through
a modem. The AUX
port must be config-
ured using the console
port before it can be
used. The AUX port
also uses the settings
of 9600 bps, 8 data
bits, no parity, 1 stop
bit, and no flow con-
trol. The speed can be
set up to 38,400 bps.
chpt_04.fm Page 241 Tuesday, May 27, 2003 9:01 AM
242 Chapter 4: Cable Testing and Cabling LANs and WANs
Summary
In this chapter, you learned the following key points:
■ Waves are energy traveling from one place to another and are created by distur-
bances. All waves have similar attributes such as amplitude, period, and frequency.
■ Sine waves are periodic, continuously varying functions. Analog signals look like
sine waves.

■ Square waves are periodic functions whose values remain constant for a period
of time and then change abruptly. Digital signals look like square waves.
■ Exponents are used to represent very large numbers. The base of a number raised
to a particular exponent is equal to the base multiplied by itself exponent times
(e.g., 10
3
= 10 * 10 * 10 = 1000).
■ Logarithms are similar to exponents. A logarithm to the base of 10 of a number
equals the exponent to which 10 has to be raised to equal the number (e.g., log
10
1000 = 3 because 10
3
= 1000).
■ Decibels are measurements of a gain or loss in the power of a signal. Negative
values represent losses and positive values represent gains.
■ Time-domain analysis is the graphing of voltage or current with respect to time
using an oscilloscope. Frequency-domain analysis is the graphing of voltage or
power with respect to frequency using a spectrum analyzer.
■ Noise is undesirable signals in communications. Noise originates from other
cables, RFI, and EMI. White noise affects all frequencies, while narrowband
interference affects only a certain subset of frequencies.
■ Analog bandwidth is the frequency range that is associated with certain analog
transmission, such as television or FM radio.
■ Digital bandwidth measures how much information can flow from one place to
another in a given amount of time. Its units are in various multiples of bits per
second.
■ It is important to have a basic understanding of these topics in order to under-
stand the cable testing concepts presented in the next lesson.
■ The OSI layer at which most of the problems on a LAN occur is the physical
layer. The only way to prevent or troubleshoot most of these problems is through

the use of cable testers. Knowledge regarding sources of noise on LAN media is
important for the proper installation of cable connectors and cabling runs.
■ A NIC provides network communication capabilities to and from a PC.
■ The three common LAN protocols are Ethernet, Token Ring, and FDDI.
chpt_04.fm Page 242 Tuesday, May 27, 2003 9:01 AM
Summary 243
■ The term Ethernet is often used to refer to all CSMA/CD LANs that generally
conform to the Ethernet specifications.
■ The Ethernet family of LAN implementations includes four main categories:
Ethernet and IEEE 802.3, Fast Ethernet, Gigabit Ethernet, and 10G or 10000-Mbps
Ethernet.
■ Use a crossover cable to connect between similar devices (like switch to switch,
router to router, PC to PC, and hub to hub).
■ Use a straight-through cable to connect between dissimilar devices (like switch to
router, switch to PC, hub to router, and hub to PC).
■ Two major types of LANs exists, peer-to-peer and client-server.
■ WANs use serial data transmission.
■ A router is usually the DTE and needs a DTE serial cable to connect to a DCE
device such as a CSU/DSU.
■ The ISDN BRI has two types of interfaces: S/T and U. To interconnect the ISDN
BRI port to the service-provider device, a UTP CAT 5 straight-through cable is
used.
■ A phone cable and an RJ-11 connector are used to connect a router for DSL service.
■ Coaxial cable and an F connector are used to connect a router for cable service.
■ Rollover cable is used to connect a terminal and the console port of a router.
To supplement all that you’ve learned in this chapter, refer to the chapter-specific Videos,
PhotoZooms, and e-Lab Activities on the CD-ROM accompanying this book.
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244 Chapter 4: Cable Testing and Cabling LANs and WANs
Key Terms

active hub Must be plugged into an electrical outlet because it needs power to
amplify the incoming signal before passing it out to the other ports.
alien crosstalk When crosstalk is caused by a signal from outside the cable.
amplitude The amplitude of an electrical signal represents its height, but it is
measured in volts instead of meters.
analog bandwidth Typically refers to the frequency range of an analog electronic
system. Analog bandwidth can be used to describe the range of frequencies transmitted
by a radio station or an electronic amplifier.
attenuation The decrease in signal amplitude over the length of a link.
AUI (attachment unit interface) The 15-pin physical connector interface between a
computer’s NIC and Ethernet cable.
crossover cable A cable that crosses the critical pair to properly align, transmit, and
receive signals on the device with line connections.
crosstalk The transmission of signals from one wire pair to nearby pairs. Adjacent
wire pairs in the cable act like antennas generating a weaker but similar electrical
signal onto the nearby wire pairs. This crosstalk causes interference with data that
might be present on the adjacent wires.
decibel An important way of describing networking signals as a unit that measures
the loss or gain of the power of a wave. Decibels are usually negative numbers repre-
senting a loss in power as the wave travels, but can also be positive values representing
a gain in power if the signal is amplified.
delay skew The propagation delays of different wire pairs in a single cable can differ
slightly because of differences in the number of twists and electrical properties of each
wire pair. Delay skew is the delay difference between pairs.
digital bandwidth Measures how much information can flow from one place to
another in a given amount of time.
ELFEXT (equal-level far-end crosstalk) A test that measures FEXT.
EMI (electromagnetic interference) Noise from nearby sources such as motors and
lights.
FEXT (far-end crosstalk) Crosstalk that occurs when signals on one twisted pair are

coupled to another pair as they arrive at the far end of a multipair cable system.
frequency The amount of time between each wave.
chpt_04.fm Page 244 Tuesday, May 27, 2003 9:01 AM
Key Terms 245
GBIC (Gigabit Interface Converter) A hot-swappable input/output device that plugs
into a Gigabit Ethernet port.
hertz The unit of measure for the frequency of an electrical signal in the number of
complete cycles per second.
IEEE 802.1X/Extensible Authentication Protocol (EAP) An alternative WLAN
security approach to WEP as specified by IEEE 802.11. IEEE 802.1X/EAP focuses
on developing a framework for providing centralized authentication and dynamic key
distribution.
impedance A measurement of the resistance of the cable to AC and is measured in ohms.
insertion loss The combination of the effects of signal attenuation and impedance
discontinuities on a communications link.
intelligent hub Sometimes called “smart hubs.” These devices basically function as
active hubs, but also include a microprocessor chip and diagnostic capabilities. They
are more expensive than active hubs, but are useful in troubleshooting situations.
logarithms Equals the exponent that a given number has to be raised to in order to
generate a certain value.
narrowband interference Noise that only affects small ranges of frequencies.
NEXT (near-end crosstalk) Computed as the ratio in voltage amplitude between the
test signal and the crosstalk signal when measured from the same end of the link.
noise As related to communications, noise refers to undesirable signals. Noise can
originate from natural and technological sources and is added to the data signals in
communications systems.
oscilloscope An important electronic device used to view electrical signals such as
voltage waves and pulses.
peer-to-peer network Networked computers act as equal partners, or peers, to each
other. As peers, each computer can take on the client function or the server function.

propagation delay A simple measurement of how long it takes for a signal to travel
along the cable being tested.
PSELFEXT (power sum equal-level far-end crosstalk (PSELFEXT) The combined
effect of ELFEXT from all wire pairs.
PSNEXT (power sum near-end crosstalk) Measures the cumulative effect of NEXT
from all wire pairs in the cable.
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246 Chapter 4: Cable Testing and Cabling LANs and WANs
pulse Determines the value of the data being transmitted. If a disturbance is deliber-
ately caused and involves a fixed, predictable duration, it is called a pulse.
repeater A device that regenerates and retimes network signals at the bit level to
allow them to travel a longer distance on the media.
RFI (radio frequency interference) Noise from other signals being transmitted nearby.
RJ-45 A connector commonly used for finishing a twisted-pair cable
sine waves Graphs of mathematical functions of many natural occurrences that
change regularly over time, such as the distance from the earth to the sun, the distance
from the ground while riding a Ferris wheel, and the time of day that the sun rises.
spectrum analyzer An electronic device that creates graphs for frequency-domain
analysis. Engineers also use frequency-domain analysis to study signals.
square waves Graphs that do not continuously vary with time. The values remain the
same for some time, then suddenly change, then remain the same, and then suddenly
return to the initial value.
straight-through cable A cable that maintains the pin connection all the way through
the cable. Thus, the wire connected to pin 1 is the same on both ends of the cable.
switch Sometimes described as a multiport bridge. While a typical bridge might have
just two ports (linking two network segments), the switch can have multiple ports,
depending on how many network segments are to be linked.
TIA/EIA-568-B standard Specifies ten tests that a copper cable must pass if it is used
for modern, high-speed Ethernet LANs.
wave Energy traveling from one place to another.

WEP (wired equivalent privacy) A security mechanism, defined within the 802.11
standard, that is designed to protect the over-the-air transmission between wireless
LAN access points and NICs.
white noise Noise that affects all transmission frequencies equally.
chpt_04.fm Page 246 Tuesday, May 27, 2003 9:01 AM
Check Your Understanding 247
Check Your Understanding
Complete all the review questions to test your understanding of the topics and con-
cepts in this chapter. Answers are listed in Appendix C, “Check Your Understanding
Answer Key.”
1. Which of the following is an 802.3u specification?
A. 10BASE-F
B. 10BASE-T
C. 100BASE-TX
D. 1000BASE-CX
2. Which of the following is the most appropriate choice for Ethernet connectivity?
A. Use 10-Mbps Ethernet as a connection between server and LAN.
B. Use Gigabit Ethernet as the link at the user level to provide good performance.
C. Use Fast Ethernet as a link between the user level and network devices to sup-
port the aggregate traffic from each Ethernet segment on the access link.
D. None of the above.
3. Which standards body created the cables and connector specification used to
support Ethernet implementation?
A. ISO
B. ANSI
C. TIA/EIA
D. IETF
4. Which of the following statements does not correctly describe a media connector?
A. An RJ-45 connector is an 8-pin connector used mainly for terminating coaxial
cable.

B. An AUI is a 15-pin connector used between a NIC and an Ethernet cable.
C. The GBIC is a transceiver that converts serial electric currents to optical
signals, and vice versa.
D. None of the above.
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248 Chapter 4: Cable Testing and Cabling LANs and WANs
5. For which of the following would you not need to provide a crossover cable?
A. Connecting uplinks between switches
B. Connecting routers to switches
C. Connecting hubs to switches
D. None of the above
6. Which technology is not a type of wireless communication?
A. Cellular
B. Wideband
C. Infrared
D. Spread spectrum
7. Which of the following is not a feature of wired equivalent privacy (WEP)?
A. WEP uses the RC4 stream cipher for encryption.
B. WEP is a security mechanism defined within in the 802.3 standards.
C. One of the goals of WEP is to deny access to the network by unauthorized
users who do not possess the appropriate WEP key.
D. None of the above.
8. Which of the following is not a WAN implementation?
A. DSL
B. ISDN
C. Frame Relay
D. Ethernet
9. What type of data-transmission method is used by a WAN?
A. Parallel
B. Serial

C. Single
D. None of above
10. What best describes a DCE?
A. User device at the end of a network
B. Equipment that serves as the data source or destination
C. Physical devices such as protocol translators and multiplexers
D. Devices that make up the network end of the user-to-network interface
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