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2.6.1 American Standard Code for Information Interchange (ASCII)
This is the most commonly used encoding scheme used to encode characters in the English language. The ASCII
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(pronounced as askee) code is a 7-bit code. So, it can only codify 2 =128 different characters. The Extended ASCII is
an eight-bit code that includes 256 characters and retains most of the ASCII codes. Extended Binary Coded Decimal
Interchange Code is an 8-bit code developed by IBM for its mainframe computers.
Table 2.10 shows characters and their ASCII codes, expressed in decimal numbers. Note that ASCII code for the
uppercase alphabet A is 65, and subsequent alphabets are assigned incrementally higher values. Thus, ASCII codes for
the characters B, C, D, … are 66, 67, 68, … . Similarly, ASCII code for the lowercase alphabet a is 97, and subsequent
alphabets are assigned incrementally higher values. Thus, ASCII codes for the characters b, c, d, … are 98,99,100, … .
and ASCII code for the digit 0 is 48, and subsequent digits are assigned incrementally higher values. Thus, ASCII codes
for the digits 1, 2, 3, … are 49, 50, 51, … .
Table 2.10: ASCII Codes
Example 49: Encode the string Age using ASCII encoding scheme.
Ans:
Letter ASCII Value 7-bit ASCII code
A 65 1000001
g 103 1100101
e 101 1100111
So, ASCII code in binary for the word Age is 100000111001011100111.
Example 50: The following data is encoded in ASCII code. Decode the data and write the equivalent characters.
1001100 1001111 1100111 1101111
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