CS 345 Data Communications

Study Guide II

Exam Friday, April 14th

 

Define and explain the following concepts  (again – no cut and paste from the Net):

 

UTP

Cancellation

STP

Shielding

CODEC

Bit Error

Fiber Optic

Burst Error

10Base2

Radio Communication Spectrum

10Base5

Baseband

RG 58

Broadband

CAT 1 – 7

ARQ

Geosynchronous satellites

Stop N Wait ARQ

Polar orbiting satellites

Go Back to n ARQ

Sampling

ASK

Parallel

FSK

Serial

PSK

BRI

QAM

PRI

FDM

EBCDIC

TDM

UNICODE

STDM

ASCII

Baud Rate

Parity bit

Bit Rate

Attenuation

Multi-mode

VRC

Single-mode

LRC

One’s complement arithmetic

CRC

PAM

Checksum

PPM

PCM

Nyquist’s Theorem

 

 

Answer the following questions:

 

1.      How does a single bit error differ from a burst error? Where does each of these types of errors occur?

 

2.      What kind of arithmetic is used to add segments in the checksum generator and checksum checker?

 

3.      Draw an Ethernet frame. Name and identify the role of each of the 7 fields.

 

4.      Describe the process, advantages, and disadvantages of stop n wait ARQ.

 

5.      What are the two types of sliding window ARQ? How do they differ from one another?

 

6.      What is the relationship of the size of the CRC remainder and the divisor?

 

7.      Organized units of data at the data-link layer are called?

 

8.      Name the seven layers of the OSI model.

 

9.      At what layer does Checksum occur?  What about VRC, LRC, and CRC?

 

10.  How do geosynchronous and polar orbiting satellites differ?  Draw a diagram of each.

 

11.  Draw a diagram of an elliptical orbiting satellite.

 

12.  List and describe 5 things that cause transmission errors.

 

13.  Draw diagrams of each of the following: coax, twisted pair, fiber optic. Identify and describe the role of each part of the media.

 

14.  What is the data capacity of a T-1 line?

 

15.  What advantages does STDM have over TDM?

 

16.  What is multiplexing? What is its main benefit?

 

17.  Which determines the bandwidth required for a transmission, bauds or bits?

 

18.  A carrier wave between two modems can be modulated in what 4 different ways?

 

19.  What is the primary responsibility of guided and unguided media?

 

20.  Calculate the VRC and LRC for the following data units using even parity.

 

                                      0111010       1101001    1111000     1010100       0101111

 

21.  What do cancellation and shielding have in common?  How do they differ?

 

22.  In an environment with many high-voltage devices, the best guided media would be?

 

23.  Convert this data unit into a polynomial.

 

                                      01000110101011101

 

24.  What is the role of the cladding in a fiber optic cable?

 

25.  What is the frequency range of the Radio Communication Spectrum?

 

26.  What are the 5 ways that radio waves can be propagated?

 

27.  Space propagation is really just another type of what propagation?

 

28.  Describe how FDM, TDM, and STDM work.  Which is most efficient? Why?

 

29.  What is a MUX?

 

30.  Given a 8 bit sequence 1101100 and a divisor of 1001, find the CRC.

 

31.  If I have two media, one with a transmission rate of 10 Mbps and one with a transmission rate of 1 MBPS and they both are affected by a burst of interference 1/10 of a second, which one will have the most errors?

 

32.  What are redundancy checks used for?

 

33.  Find the Checksum for the following data:

 

                                      10100001101010101110111101010011

 

34.  What is the most efficient error correction method? Why?