DATA CODES
Presented by:
Zeeshan Abbas
Outline
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Data code meaning
ASCII
BAUDOT
BCD
EBCDIC
Unicode
What's the data code
• This refers to the way in which data is
represented.
• The sender and receiver must use the same
code in order to communicate properly.
• Here, we will briefly look at some common
codes.
Binary Code
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ASCII
BAUDOT
BCD
EBCDIC
Unicode
ASCII
• ASCII, which stands for “The American
Standard Code for Information
Interchange,”.
• introduced by the American National
Standards Institute (ANSI) in 1963.
• It is the most commonly used character code.
• In an 8-bit context, the leading bit is set
to 0; thus ASCII can be thought of as the
“bottom half” of an8-bit character code.
The ASCII character set
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CR = “carriage return” (MSDOS: move to beginning of line)
LF = “line feed” (MSDOS: move directly one line below)
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SPC = “blank space”
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• To work out a particular value from the table,
you first determine the row value, then add
the column value. For example, the character
A has a value of 41, being a row value of 40
and a column value of 1.
The Baudot Code
• The Baudot code, invented by the Frenchman
Emile Baudot in 1870.
• The Baudot code was used extensively in
telegraph systems.
• Using five bits allowed 32 different characters.
Paper tape with holes representing the "Baudot Code"
How the baudot code works
• Each character is preceded by a start bit, and
followed by a stop bit.
• For instance, lets consider coding the phase
“ABDI-RIZAK SAYS HELLO!“
Binary-coded decimal (BCD)
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Every four bits represent one decimal digit.
 Use decimal values
from 0 to 9
Example
• 709310 = ? (in BCD)
7
0111
0
0000
9
1001
3
0011
• Multi-digit decimal numbers are stored as
multiple groups of 4 bits per digit.
EBCDIC
• EBCDIC (Extended Binary Coded Decimal
Interchange Code
(pronounced ebb’-se-dick)
• 8-bit code
• Developed by IBM
• Rarely used today
• IBM mainframes only
UNICODE
• 16-bit standard
• Developed by a consortia
Intended to supersede (replace) older 7- and 8bit codes