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# Assignment No. 5 Semester Spring 2012

Assignment No. 5
Semester Spring 2012
Data Communication - CS601

Total Marks: 20

Due Date: 00-07-2012

Objective: To understand the concept related to the error detection mechanism.

Instructions:

Assignment should be in your own wordings not copied from net, handouts or books.

It should be clear that your assignment will not get any credit (marks) if:

• The assignment is submitted after due date.
• The submitted assignment does not open or file is corrupt.
• The assignment is copied (from other student or copied from handouts or internet).
• Student ID is not mentioned in the assignment File or name of file is other than student ID.

For any query about the assignment, contact at cs601@vu.edu.pk

GOOD LUCK

Q. 1. Suppose a sender sent a word “assignment” for which the receiver received the following binary:

“01100001011010010111001101101001011001110110111001101110011001010110111001110100”

By applying the complete process of LRC using even parity, you are required to check that, is the same word received by the receiver or not? Also write the word received by the receiver.

 Binary Code Alphabet Binary Code Alphabet Binary Code Alphabet Binary Code Alphabet 0110 0001 a 0110 1000 h 0110 1111 o 0111 0110 v 0110 0010 b 0110 1001 i 0111 0000 p 0111 0111 w 0110 0011 c 0110 1010 j 0111 0001 q 0111 1000 x 0110 0100 d 0110 1011 k 0111 0010 r 0111 1001 y 0110 0101 e 0110 1100 l 0111 0011 s 111 1010 z 0110 0110 f 0110 1101 m 0111 0100 t 0110 0111 g 0110 1110 n 0111 0101 u

Table 1

HINT: First convert the word “assignment” into binary equivalent with the help of the given table 1.

The LRC calculated by the sender is not appended with the given binary. It is also your task to calculate the LRC by yourself.

Note:

• Assignment should be in your own wordings not exactly copied from Internet, handouts or books.

Views: 6583

### Replies to This Discussion

Naveed Akbar

we dont have to mention which bits are corrupted and which are not ... we just have to simply find the LRC of both words and to tell either the words are same or not

You are not required to tell the corrupted bits but you must have to mention the word, received by the receiver.

ye wala ????? kp bhai

AQSA

Definition: Even parity: In asynchronous communications, an error-checking technique that sets an extra bit (called a parity bit) to 1 if the number of 1 bits in a one-byte data item adds up to an even number. The parity bit is set to 0 if the number of 1 bits adds up to an odd number. See odd parity and parity checking.

Zahoor Elahi

even parity means u have to make the total EVEN ..... if its 11 then its total is 2 .... so it will be 11=0 .... if ur going to make it 11=1 this means u r adding 1 in 2 and it will be (3)odd ....... count all the 1's and see if the total is even or not .... if its even then put ZERO and if its odd then put ONE :)

A

# Please read it carefuller this is the procedure for odd parity so i think i calculated correct

Aparity checking error control method that improves on the simple vertical redundancy check (VRC) by viewing data as a block, or data set. As shown in Table L-1, this approach is characterized in terms of the manner in which human beings add numbers, not only in columns, but also in rows across columns, as though the devices were viewing data set in a matrix format. This additional technique of checking the total bit values of the characters on a longitudinal (i.e., horizontal) basis employs the same parity (i.e., odd or even) as the vertical check technique in the example in Table L-1. LRC and VRC are easily and inexpensively implemented in devices employing asynchronous transmission. LRC adds a significant measure of reliability when used in conjunction with VRC, although compensating errors still can occur in non-adjacent characters.The LRC is sent as one or two extra characters, known as block check characters (BCCs), at the end of each data block. See also error controlparity check, and VRC.
##### Table L-1: Longitudinal Redundancy Check (LRC)
Bit/Value C O N T R O L Odd Parity
1 1 1 0 0 0 1 0 0
2 1 1 1 0 1 1 0 0
3 0 1 1 1 0 1 1 0
4 0 1 1 0 0 1 1 1
5 0 0 0 1 1 0 0 1
6 0 0 0 0 0 0 0 1
7 1 1 1 1 1 1 1 0
8 (Odd Parity) 0 0 1 0 0 0 0

Webster's New World Telecom Dictionary Copyright © 2010 by Wiley Publishing, Inc., Indianapolis, Indiana. Used by arrangement with John Wiley & Sons, Inc.

See LRC in Computer

its odd parity not even parity in even parity it will be like this ....

1 1 0 0 0 1 0

1 1 1 0 1 1 0

0 1 1 1 0 1 1

0 1 1 0 0 1 1

0 0 0 1 1 0 0

0 0 0 0 0 0 0

1 1 1 1 1 1 1

..............

1 1 0 1 1 1 1          ............ this will be the even parity

is your point clear now?  Zahoor Elahi

Aqsa kindly ap he in dono i mean aisignnent and assignment ka LRC bta dain???

Please see the attached file for the solution ...... thnx!

Attachments:

Thanx Aqsa so nice of u. Allah bless u

i can not understand that how we know that "you are required to check that, is the same word received by the receiver or not? Also write the word received by the receiver. "

Sweet Butt

write the binary code of word "assignment" using the table

then write the word of the binary code already given using the table

write the LRC of both words

both words will be different....

1

2

3

4

5

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