1.What is the difference between
the bit rate and baud rate?
µÍº. bit rate à»ç¹ÃٻẺ¡ÒÃÊ觢éÍÁÙÅ
0 ¡Ñº 1
baud rate à»ç¹àÇÅÒ·Õèãªé㹡ÒÃÊ觢éÍÁÙŢͧáµèÅÐ
baud rate
2. Define digital transmission.
Define analog transmission. What is the difference between digital
and binary?
µÍº. digital
transmission à»ç¹¡ÒÃÊ觢éÍÁÙÅà»ç¹ÃËÑÊ
0 , 1
analog transmission à»ç¹¡ÒÃÊ觢éÍÁÙÅẺ¤Å×è¹
3. Explain the main propagation
effects.
µÍº. distortion
¡ÒúԴàº×͹
noise
¤Å×è¹Ãº¡Ç¹
interference ¡ÒÃá·Ã¡á«§
4. What are the three main wire
transmission media? Which is used most frequenly to the desktop?Why?
Which is used most
frequenly over longer distances?Why?
µÍº.wire transmission
media Ê×èÍ·Õèãªéª¹¡ÒÃÊ觢éÍÁÙÅ
optical fiber àÊé¹ãÂá¡éǹÓáʧ
à¾ÃÒÐÁÕ¤ÇÒÁàÃçÇÊÙ§
Êè§ÊÑÒ³ä´é´Õ
áÅж١µéͧ·ÕèÊØ´
5. As bandwidth increases
in a channel, how dose maximum transmission speed through
that channel
change? What dose broadband mean literally?How is the term broadband
commonly used?
µÍº. broadband ¡ÒÃãªéªèͧÊÑÒêèͧà´ÕÂÇ
6. In PC serial ports, how many
pins are used for data transmission?In general,what arrre other pins for?
µÍº. PC serial post ÁÕ 2 ª¹Ô´
9 pin áÅÐ 11 pin
pin ÁÕäÇéà¾×è͵èÍàª×èÍÁ¡ÑºÍØ»¡Ã³ìµèÒ§æ
7. Define modulation. Define
demodulation. Do not just translation between digital and analog
or analog
digital. For both modulation and demodulation, characterize
whether the transmission line is analog or
digital and whether the device attached to the transmission line is analog
or digital.
µÍº. modulation á»Å§ÊÑÒ³
digital à»ç¹ analog
demodulation á»Å§ÊÑÒ³
analog à»ç¹ digital
8. Which modem form is easier to
install - internal or external? What is the advantage of internal modem
over external modems? What is the most expensive modems form?
µÍº. àÅ×Í¡ãªéẺ
external à¾ÃÒÐÍÂÙèÀÒ¹͡·ÓãËé¡ÒõԴµÑé§áÅжʹªèÍÁáªÁ§èÒÂ
9. What is the speed of a V.34 modems?
What are the speed of a V.90 modem? Be specific.
µÍº. V.34 modam speed = 33.6 kbps
V.90 modam speed = 33.6 kbps sending
and 56 kbps receiving
10.What is " tranining "
in initial modem communication? If a V.42 modem tries to communication
with
a 14.4 kbps
V.32 bis modem,what will happen?
µÍº. tranining à»ç¹¡ÒûÃѺãËé
modem 2 ẺÊ觢éÍÁÙÅÊ×èÍÊÒáѹä´é
11.What is the maximum reception
speed for V.90 modems? What is the maximum transmision speed?
To use a V.90 modem,
can you use your ordinary home telephone line,or do you need additional
line?
µÍº. speed 㹡ÒÃÊ觢éÍÁÙÅÊÙ§ÊØ´¢Í§
V.90 ¤×Í 56 kbps
12.Distinguish between
full-duplex and half-duplex transmission in
terms of who can communicate
simultaneousiy.
What is flow control, and why dose full-duplex transmission
allow it? What is error
correction,
and why dose full-duplex transmission allow it?
13.Distinguish between serial and parallel transmission in tems of bit rate for a given clock cycle?
14.In ISDN, what is
2B+D? What is maximum reception speed for
ISDN? What is the maximum
transmission speed?
µÍº.ISDN modem à»ç¹ modem ·ÕèÊÒÁÒöµèÍÍØ»¡Ã³×Ê×èÍÊÒÃä´é
2 ª¹Ô´ ¤×Í 2B+D
B ¤×Í ªèͧÊè§ÊÑÒ³
D ¤×Í µÑǴǺ¤ØÁªèͧ
B
15.What is multipiexing?How dose
it apply to ISDN?
µÍº. multipiexing ¤×Í ªèͧÊÑÒ³ÃÇÁ¢Í§ÍØ»¡Ã³ìËÅÒÂæÍÂèÒ§
à»ç¹ÃкºÊè§ÊÑÒ³¢Í§
ISDN modem
16.What type of organization offers
cable modems? What type of organization offers digital
subscriber
lines(DSLs)?
µÍº. cable modem Êè§ÊÑÒ³â´ÂãªéÊÒÂà¤àºÔÅ
DSL modem ÁÕªèͧÊÑÒ³â·ÃÈѾ·ì
·ÓãËéÊÒÁÒöãªéâ·ÃÈѾ·ìä´é
17.When you use an alternative to ordinary modem transmission, what four additional costs do you incur?
18.If you have a digital device
communicating over an analog transmission lian,what type of translation
device do you need,if
any?If you have a analog device communicating over digital
transmission lian,
what type of translation
device do you need,if any?If you have a digital device communicating
over an
digital transmission
lian, what type of translation device do you need,if any?
µÍº. -ISDN modem
-DSL modem
-Cable modem