This document provides information about various computer peripheral and network devices. It describes input devices like keyboards, mice, and scanners. It outlines output devices such as monitors, printers, and speakers. Storage devices covered include hard drives, flash drives, CDs/DVDs, and tape. The document also discusses network interface cards, hubs, switches, routers, and servers. It provides brief explanations of modems, data transmission rates, and common network types.

1. Peripheral Devices

2. Device Drivers
• A program to tell the system software how to
work with that piece of hardware
• Some common device drivers are built in the
system software (Operating System) e.g.
keyboard and mouse drives

3. Plug-n-Play Devices
• Devices designed such that Windows can
detect them, install and configure the device
driver automatically
• For non plug-n-play devices, we have to install
and configure the device driver manually.

4. Input Devices (1)
• Keyboard
• P/S2 keyboard
• USB keyboard
• Wireless keyboard

5. Input Devices (2)
• Pointing Devices
• Mouse, trackball, touch pad, light pen, digitizer
• Touch screen

6. Input Devices (3)
• Scanning devices
• Image scanner
• Fax machine – scan image to bitmap
• Bar code scanner – scan Universal Product Code
(UPC)
• Magnetic ink character scanner (MICR)
• Optical character scanner (OCR)
• Optical mark scanner (OMR)

7. Input Devices (4)
• Voice Input Device
• Microphone – to receive the sound signal
• Sound card – to convert the sound signal to digital
form
• Use speech recognition software to recognize
human speech

8. Input Devices (5)
• Handwriting Recognition Device
• Need handwriting recognition software
• Called natural input
• Slow inputting speed

9. Output Devices (1)
• Visual Display Unit (VDU)
• Commonly called monitor
• 2 common types of monitor
• CRT (Cathode Ray Tube) monitor
• High radiation and bulky
• LCD (Liquid Crystal Display) monitor
• No radiation and slim

10. Output Devices (2)
• Printer – to produce hard copy
• Laser printer
• to produce high quality output
• resolution up to 2400 dpi (dot per inch)
• use carbon toner, usually for black and white
printout, colour is very expensive

11. Output Devices (3)
• Inkjet printer
• produce good quality colour output
• resolution up to 1440 dpi
• use ink droplets to compose the image
• The printer is much cheaper than laser printer but
the ink is very expensive

12. Output Devices (4)
• Dot matrix printer
• Use impact principle
• Can print multiple (carbon) copies at a time,
usually use in printing invoices
• The ink ribbon is cheap
• Poor quality of printout

13. Output Devices (5)
• Plotter
• Drawing high quality image, use colour pens, can
draw smooth curves
• Can print on large paper size, use roll of paper
• To draw posters and maps
• Use in CAD (Computer Aided Design)

14. Output Device (6)
• Voice output devices
• Sound card, to convert computer signals to sound
• Speakers, to amplify the sound output

15. Storage Devices (1)
• Floppy Disk (Diskette)
• A flexible plastic circular disc
• Packed in a plastic square jacket
• Formatted to 1.44MB
• Divided to many circular tracks
• Each track is divided to many sectors
• Use magnetic technology to store data ‘0’ or ‘1’
• Random access
• Slow accessing speed

16. Storage Devices (2)
• Hard Disk
• High storage capacity, over 100 GB
• Hard metallic surface
• Consists of several metallic disks
• Data are stored in cylinder (a deck of tracks)
(see p.86)
• Use magnetic technology
• Very high access speed
• Random access

17. Storage Device (3)
 Optical disk
› CDROM, DVDROM, CDRW, DVDRW
› Use optical technology, laser reflection on pits
› ‘1’ will reflect the laser beam while ‘0’ does
not
› High storage capacity, 700 MB for a CDROM,
17GB for a DVDROM
› Random access
› High access speed

18. Storage Device (4)
• Tape
• Cheap
• Sequential access
• Use magnetic technology
• Ideal for backup data, we need to backup and restore all
data
• High storage capacity
• Slow access speed
• Group of records are stored in a block
• Inter-block gaps are needed for stopping and starting the
read/write head.

19. Storage Device (5)
• Other Storage devices – can be read/write
• Removable disks -Zip disk(100/250MB),
superdisk(120MB), Jazz disk(1GB)
• Flash memory cards – compact flash, smart
media and memory stick, commonly used in
digital camera

20. Network Devices (1)
• Network Interface Card (NIC) (LAN card)
• Connection between the network and the computer bus
• Have built-in transceiver, for data transmitting and receiving
• Usually 100 MB/s
• Wireless LAN card
• Usually 11 MB/s
• Work within the distance range, and no blocking in between.

21. Network Devices (2)
• Connectors
• RJ-45 telephone jack connector
• For connecting twisted pairs LAN cable
• BNC connector
• For connecting coaxial cables

22. Network Device (3)
• Terminators
• Use in bus network, to prevent signal rebounce
and echo at the ends of bus.

23. Network Device (4)
• Hub
• To connect the workstations within a room on
same floor
• Switch
• To connect the workstations for different floors in
a building, it is faster and more efficient than a
Hub.
• Router
• To connect different LANs together to form a Wide
Area Network (WAN)

24. Network Device (5)
• Repeater
• When a network spans a long distance, the signal
weaken, repeater is used to reproduce the signal.
• Exchange
• To boost the signals along the network path for a
Wide Area Network.

25. Network Device (6)
 Computer
› Different computers play different roles on a
network
 Server
› Provide services to other computers connected
to the network, usually have higher processing
power and larger storage capacity.
 Workstation
› The computers connected to the network but not
act as a server.

26. Network Device (7) - Servers
• File server
• control the sharing and access of files over the network,
must have a huge storage capacity.
• Print server
• Manage the print jobs from different computers to
different network printers, and manage the print queues.
• Web server
• To host a web site and publish web pages on the web,
support HTML, Java script, CGI, PHP and ASP web
languages
• Email server
• To store, send and receive emails over the Internet
• Internet server
• To provide Internet access

27. Communication Device
• Modem - Modulator-demodulator
• It transforms digital signals of computer to analog
signals to be transmitted through telephone lines.
(Modulation)
• It also transforms analog signals back to digital
signals for the computer that receives the signals.
(Demodulation)

28. Data/Signal Rate
 Data Rate
› Refer to the no. of bits per second sent
 Signaling Rate (Baud Rate)
› Refer to the no. of signals per second sent
› Each signal may consists of several bits e.g. 101
 Bandwidth
› The frequency range of a particular media
› is directly proportional to the data rate

29. Types of network
• Client-Server Network
• Some computers act as server to provide services to
clients on the network
• Server programs are running on the server
• Client programs are running on client computers
• Peer-to-peer Network
• Every computer plays the same role in the network. They
form a workgroup, no server and no client
• The security in a peer-to-peer network is low.
• It is easy to set up, since no server programs or client
programs need to be run.