02 Understanding Electronic Communication

Revision no.: PPT/2K403/02

UnderstandingElectronic

Communication

Revision no.: PPT/2K403/02©

CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

Computer Communication

Dots and Dashes, Bits and Bytes

Early radio communication used Morse codes for

transmissions.

It is based on assigning a series of pulses to represent each

letter of the alphabet.

In Morse code any single transmitted value had two possible

states: a dot or a dash.

This on–off notation can also be used to provide two numbers,

0 and 1


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

Dots and Dashes, Bits and Bytes

The value 0 represents no signal, or off, and the value 1

represents a signal, or on, state.

It is called binary notation because it uses only two digits 0

and 1.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

The Binary Language of Computers

It is the fundamental to understanding PC technology.

Bits

A bit is the smallest unit of information that is recognized by a

computer: a single on or off event.

Bytes

A byte is a group of 8 bits. It is required to represent one

character of information.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

The Binary Language of Computers (contd.)

It is the standard unit by which memory is measured in a computer.The table that follows lists units of computermemory and their values:

8 bits (equal to one character) Byte

4 bits (half of a byte) Nibble

Smallest unit of information; shorthand term for binary digit

Bit

Value Memory Unit


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

The Binary Language of Computers (contd.)

1,073,741,824 bytes (approximately 1 billion bytes or 1024 MB)

Gigabyte (GB)

1,048,576 bytes (approximately 1 million bytes or 1024 KB)

Megabyte (MB)

1024 bytes Kilobyte (KB)

16 bits on most personal computers (longer words possible on larger computers)

Word

Value Memory Unit


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

The Binary System

The binary number system uses the base of 2 (0 and 1).

A bit can exist in only two states.

0 equals off.

1 equals on.

The binary system has a base of 2, the numbers 0 and 1.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

The Binary System (contd.)

Counting in Binary Notation

Binary notation uses the same system of right-to-left columns of ascending values.

The factor used in the binary system is 2.

Examples

Byte—Example A

The value of this byte is 0 because all bits are off (0 = off).

0 0 0 0 0 0 0 0 8 bits

128 64 32 16 8 4 2 1 # value


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.


Byte—Example BTwo of the bits are turned on (1 = on). The total value of this byte is determined by adding the values associated with the bit positions that are on. It represents the number five.

0 0 0 0 0 1 0 1 8 bits128 64 32 16 8 4 2 1 # value

Byte—Example C Two different bits are turned on to represent the number 9 (8 + 1).


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.


Byte—Example C

0 0 0 0 1 0 0 1 8 bits

128 64 32 16 8 4 2 1 # value

The factor used in the binary system is 2.

A single byte can represent a single byte.

The following represents the Decimal Number and the

Binary equivalent.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.


0110 6

0101 5

0100 4

0011 3

0010 2

0001 1

0000 0

Binary Equivalent Decimal Number


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.


1001 9

1000 8

0111 7

Binary Equivalent Decimal Number


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

Parallel and Serial Devices

In serial devices a single bit is sent at a time.

In serial the data is sent one after the another since it is a

single line.

In parallel 8 bits sent at once.

In parallel, all the data are sent simultaneously.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

Parallel and Serial Devices (contd.)


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code

It is the standard code for handling text characters on most

modern computers is called ASCII.

It consists of 128 codes representing the English alphabet,

punctuation, and certain control characters.

The extended character set contains the original 128 and

an additional 128 codes.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

The following 4 bytes represent the text string 12AB (using

ASCII code):

00110001 00110010 01000001 01000010 1

2 A B

The following table is a partial representation of the ASCII

character set.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

55 00110111 7

54 00110110 6

53 00110101 5

00110100

00110011

00110010

00110001

00110000

Binary 1 Byte

52 4

51 3

50 2

49 1

48 0

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

70 01000110 F

69 01000101 E

68 01000100 D

01000011

01000010

01000001

00111001

00111000

Binary 1 Byte

67 C

66 B

65 A

579

56 8

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

78 01001110 N

77 01001101 M

76 01001100 L

01001011

01001010

01001001

01001000

01000111

Binary 1 Byte

75 K

74 J

73 I

72 H

71 G

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

86 01010101 V

85 01010101 U

84 01010100 T

01010011

01010010

01010001

01010000

01001111

Binary 1 Byte

83 S

82 R

81 Q

80 P

79 O

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

100 01100011 d

99 01100010 c

98 01100001 b

01011010

01011001

01011000

01010111

01010110

Binary 1 Byte

97 a

90 Z

89 Y

88 X

87 W

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

108 01101011 l

107 01101010 k

106 01101001 j

01101000

01100111

01100110

01100101

01100100

Binary 1 Byte

105 i

104 h

103 g

102 f

101 e

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

116 01110010 t

115 01110010 s

114 01110001 r

01110000

01101111

01101110

01101101

01101100

Binary 1 Byte

113 q

112 p

111 o

110 n

109 m

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

ASCII Code (contd.)

122 01100111 z

01100101

01100100

01100011

01100010

01100001

Binary 1 Byte

121 y

120 x

119 w

118 v

117 u

Decimal Symbol


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

The Computer Bus

The computer moves information through a bus.

A bus is a group of electrical wires running parallel to one

another that can carry a charge from one point to another.

On a circuit board they appear as copper traces.

They are found in multiples of eight 8, 16, 32, 64, and so

on.s


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

The Computer Bus (contd.)


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.


It allows any device to receive information from or send

information to any other device on the same bus.

It provides a common path along which to transmit

information in the form of code

A bus is a set of parallel wires or lines to which the CPU,

the memory, and all input/output devices are connected.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.


The address bus contains one line for each bit needed to

give the address of a device or a location in memory.

The data bus contains one line for each bit of data being

transmitted from device to device.


CM

S IN

STIT

UTE

, 200

4. A

ll rig

hts

rese

rved

. No

part

of th

is m

ater

ial m

ay b

e re

prod

uced

, sto

red

or e

mai

led

with

out t

he p

rior p

erm

issi

on.

Design & Published by: CMS Institute, Design & Development Centre, CMS House, Plot No. 91, Street No.7,

MIDC, Marol, Andheri (E), Mumbai –400093, Tel: 91-22-28216511, 28329198Email: [email protected]

www.cmsinstitute.co.in

Expect the world from us

02 Understanding Electronic Communication

Documents

Transcript of 02 Understanding Electronic Communication