Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

118 CHAPTER 7 Wide Area Networking
5. What is the difference between ISDN and dial-up
A. Both use dialing, but dial-up is based on the WAN and use analog lines,
whereas ISDN and DSL are both digital.
B. Neither use dialing, but dial-up is based on the telephone system and
use analog lines, whereas ISDN and DSL are both analog.
C. Both use dialing, but dial-up is based on the telephone system and use
digital lines, whereas ISDN and DSL are both digital.
D. Both use dialing, but dial-up is based on the telephone system and use
analog lines, whereas ISDN and DSL are both digital.
Answers
1. Correct answer and explanation: B. When working with ISDN technology,
always remember that the transmission rate of a single BRI ISDN B channel
is 64 Kbps.
Incorrect answers and explanations: A, C, and D. Answer A is incorrect
because the rate is 64 Kbps, not 56 Mbps. Answer C is incorrect because
the rate is 64 Kbps, not 128 Kbps. Answer D is incorrect because the rate
is 64 Kbps, not 256 Mbps.
2. Correct answer and explanation: C. ISDN provides better speed, connection
time, and reliability compared with a modem. ISDN can be
connected to systems in many ways because of the different adapters
that can be used with it. ISDN circuits will be terminated on a device or
within a location, not on a modem, or on individual workstations using
modems.
Incorrect answers and explanations: A, B, and D. Answer A is incorrect
because ISDN circuits will be terminated on a device or within a location,
not on a modem, or on individual workstations using modems. Answer
B is incorrect because ISDN circuits do not terminate on workstations.
Answer D is incorrect because ISDN circuits will be terminated on a device
or within a location, not on a modem, or on individual workstations using
modems.
3. Correct answer and explanation: D. BRI ISDN provides up to 128 Kbps.
Incorrect answers and explanations: A, B, and C. Answer A is incorrect
because a T1 is a dedicated connection, it’s always on, and you always pay
for its use. It’s also 1.544 Mbps. Answer B is incorrect because a T3, much
like a T1, is a dedicated connection providing up to 45 Mbps. Answer C is
incorrect because a 56 Kbps leased line will only provide up to 56 Kbps.
4. Correct answer and explanation: A. If there is no dial tone on the line, you
will not be able to dial out to the RAS server to connect to your corporate
network. For the Network+ exam, you will be expected to troubleshoot
many scenarios; so make sure you read them very carefully.
Incorrect answers and explanations: B, C, and D. Answer B is incorrect
because neither the modem nor the PC is the problem; the problem is