Upload
cindy
View
65
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Personal Computer Data Communications . Digital Data. Data in a computer is stored as a series of bits , or binary digits. Each bit is a one or a zero, represented in a computer by electrical, magnetic and optical technology . Digital Data. - PowerPoint PPT Presentation
Citation preview
CIS 103 — Applied Computer Technology
Last Edited: September 17, 2010by C.Herbert
Personal Computer Data Communications
CIS 103 Applied Computer Technology
Digital Data
Data in a computer is stored as a series of bits,
or binary digits.
Each bit is a one or a zero,
represented in a computer
by electrical, magnetic and
optical technology.
Data Communications 2
CIS 103 Applied Computer Technology
Digital Data
Every object in a computer’s memory is stored as a series of bits.
Data Communications 3
Numbers
CIS 103 Applied Computer Technology
Digital Data
Every object in a computer’s memory is stored as a series of bits.
Data Communications 4
Text
CIS 103 Applied Computer Technology
Digital Data
Every object in a computer’s memory is stored as a series of bits.
Data Communications 5
Pictures
CIS 103 Applied Computer Technology
Digital Data
Every object in a computer’s memory is stored as a series of bits.
Data Communications 6
Sound
CIS 103 Applied Computer Technology
Digital Data
Every object in a computer’s memory is stored as a series of bits.
Data Communications 7
Video
… every object is stored as a series of bits.
Digital Data
01000001 01000010 01000011 01000100 01000101 01000110 01000111 01001000
CIS 103 Applied Computer Technology Data Communications 9
Bits can be moved in groups over several parallel wires at the same time.
or one at a time over a single wire …
Data Communications 9
0 1 0 0 0 0 0 1 0 1 0 0 0 0 1 0
0 1 0 0 0 0 1 00 1 0 0 0 0 0 1
Serial Communication
ParallelCommunication
Parallel and Serial Communication
Data Communications 10
Parallel communication uses a set of wires called a data bus, so it is:
• faster• more expensive• often used for short distances (inside a computer)
0 1 0 0 0 0 1 00 1 0 0 0 0 0 1
Data Bus
The size of the data bus affects a computer’s
word length.
An 8-bit word
Serial and Parallel Communication
CIS 103 Applied Computer Technology Data Communications 11
Serial communication:• is not as fast • is less expensive
• is often used for long distances (between computers)• requires only one data wire• often uses two data wires– one in each direction
0 1 0 0 0 0 0 1 0 1 0 0 0 0 1 0
Serial Communication
Serial and Parallel Communication
CIS 103 Applied Computer Technology
Data Communication Standards
a communications protocol defines:
• the electronic signals to be used
• how fast the data should be sent
• error checking methods
• and other technical details
Data Communications 12
CIS 103 Applied Computer Technology
Data Communication Standards
A data communication standard includes:
• a communications protocol
• the type of connectors to be used
• the type cables to be used
Data Communications 13
CIS 103 Applied Computer Technology
Data Communication Standards
Several agencies and associations maintain data communications protocols and standards:
• International Telecommunications Union (ITU) – a technical committee sponsored by the United Nations
• Institute of Electrical and Electronics Engineers (IEEE) – a professional group
• Electronics Industries Association (EIA) – a trade association
Data Communications 14
CIS 103 Applied Computer Technology
Data Communication Standards
Three commonly used serial communications standards are:
• RS-232c
• USB
• Firewire
Data Communications 15
CIS 103 Applied Computer Technology
RS-232c
The RS-232c standard:• was created by the IEA in 1969 for terminals
connected to old mainframe computers
• Used with early personal computers and telephone modems
• not used as much today, but is still used with some printers and older equipment
Data Communications 16
CIS 103 Applied Computer Technology
RS-232c
There are two types of RS232c connectors
• 9-pin
• 25-pin
Data Communications 17
CIS 103 Applied Computer Technology
USB
In the 1990’s several computer companies formed a new trade association – the Universal Serial Bus Implementers Forum (USB-IF) – to develop a faster and less expensive data communication standard using newer technology. Their popular new standard is called USB (Universal Serial Bus).
Data Communications 18
CIS 103 Applied Computer Technology
USB
USB is now the most widely used data communication standard for connecting devices to personal computers.
Data Communications 19
CIS 103 Applied Computer Technology
USB
Three common versions of USB:
• USB USB 1.1 (1994)12 mbps (megabits per second), cables up to 3 meters
• Hi-Speed USB USB 2.0 (2001) 480 mbps, 5 meters
• SuperSpeed USB USB 3.0 (2008) 5 gbps (gigabits per second), 5 meters
Data Communications 20
CIS 103 Applied Computer Technology
USB Connectors
Data Communications 21
There are six different types of USB connectors.
… more about USB in the next lesson
CIS 103 Applied Computer Technology
Firewire
• first developed by Apple Computers • approved as standard IEEE 1394 in 1995• Sony’s version is iLInk, Texas Instruments’ is Lynx • is the High Definition Audio-Video Network Alliance
(HANA) standard for the audio visual industry • The automobile industry, the military, and the NASA
Space Shuttle all use Firewire
Data Communications 22
CIS 103 Applied Computer Technology
Firewire
Two common versions of Firewire:
• Firewire 400 (IEEE 1394a) has a maximum data transfer rate of 400 Mbps
• Firewire 800 (IEEE 1394b) is capable of 800 Mbps over standard cables and up to 3,200 Mbps using fiber optic cables
Data Communications 23
CIS 103 Applied Computer Technology
Firewire Connectors
Both 6-pin and 4-pin Firewire connectors are common
Data Communications 24
CIS 103 Applied Computer Technology
Firewire vs. USB
• Firewire is faster and more sophisticated than USB
• Is capable of longer distances (up to 100 meters)
• the equipment is significantly more expensive
• It can be a little harder to use
• USB is far more common for connecting devices to personal computers.
Data Communications 25
CIS 103 Applied Computer Technology
Next . . .
Connecting USB devices to a personal computer
Data Communications 26