A/L Information & Communication Technology Ishani
Narahenpita
CODING SYSTEMS
• Computer works only with binary numbers. It stores all
types of data in the form binary digits. The data is
converted to binary form before it is stored inside the
computer the process of converting data into binary form
is known encoding. Data can be converted into binary
form by using different coding schemes.
• BCD (binary coded decimal)
• Unicode
BCD (BINARY CODED DECIMAL)
decimal. It is a 4-bit code. It
means that each decimal digit is
represented by 4 binary digits. It
was used by early computers.
• This is used to represent the
numbers from 0-9.
BCD (BINARY CODED DECIMAL)
• Write the relevant BCD code of 1 and 3.
1 3
EBCDIC (extended binary coded decimal interchange) coding
systems
• EBCDIC stands for extended binary coded
decimal interchange code. It is an 8-bit code. It
is normally used in mainframe computers. It
can represent 256 (28) characters.
A/L Information & Communication Technology Ishani
Narahenpita
ASCII (AMERICAN STANDARD CODE FOR INFORMATION)
ASCII stands for American standard code for
information interchange. It was published in 1968 by
ANSI (American national standard institute). It is the
most widely used coding scheme for personal
computers. The 7-bit code can represent 128
characters. It is not enough to represent some
graphical characters displayed on computer screens.
An 8-bit code can represent 256 characters. The
extended 128 unique codes represent graphic
symbols.
• According to ascii there are unique code to represent each
character in keyboard.
A/L Information & Communication Technology Ishani
Narahenpita
A/L Information & Communication Technology Ishani
Narahenpita
ASCII (AMERICAN STANDARD CODE FOR INFORMATION)
• Find decimal ASCII code for.
H=72, e=101, 1=108, o=111 72 101
108 108 111
ASCII (American Standard Code for Information)
A/L Information & Communication Technology Ishani
Narahenpita
• Unicode is a 16-bit code and it could represent
65536 characters when it was introduced in
1991. In 1996 new version of UNICODE
introduced and it is capable of representing
1,114,112 characters and up to now all together
90 worldwide alphabets are represented by
Unicode (including Sinhala alphabet)
the world.
0B80
0B81
0B82
Tamil
