Media and their applications

1. Media and their applications Chapter 2

2. Chapter Overview • Types of Network • Circuit Switched & Packet Switched • Signaling Techniques • Baseband & Broadband • Interference • Transmission Medium • Wired & wireless Prepared by Saher H. Mohammed

3. Types of Networks • There are two kinds of networks over which data can be transmitted. • Circuit switched network • Packet switched network Prepared by Saher H. Mohammed

4. Circuit Switched Network • In a circuit switched network, there is a dedicated and a direct physical connection between the sender and the receiver. • No other transmission can take place while the connection is active. • Once the current transmission is ended, other connections can be made. • Ideal for voice communication as no interruption from other devices. Prepared by Saher H. Mohammed

5. Packet Switched Network • This network requires data transmission be broken into smaller units called packets. • Each packet is sent independently through the network. • It is used for data transmission because data is not as time-sensitive as voice communication. • It allows multiple devices to share one line or frequency. • It facilitates error correction. Prepared by Saher H. Mohammed

6. Signaling Techniques • There are two ways to send a signal over a medium. • Baseband signaling • Broadband signaling Prepared by Saher H. Mohammed

7. Baseband Signaling • Sends one data signal across the network media. • Entire capacity of the media is used for the one data signal. • Signals are transmitted in a digital format. • Many devices can send and receive across the medium, but only one at a time. • Used for computer network data transmissions. Prepared by Saher H. Mohammed

8. Broadband Signaling • Divides the cable into several different channels. • Signals are transmitted at different frequencies in an analog mode. • Allows many different signals to be sent simultaneously on a single cable. • Signal sent in only one direction. Prepared by Saher H. Mohammed

9. Factors Affecting the Transmission • The flow of a signal down the network media can become distorted. • Common types of distortions are attenuation and interference. Prepared by Saher H. Mohammed

10. Attenuation • Attenuation is the loss of signal power. • Measured by the decrease in decibels (db) over a specific distance. Prepared by Saher H. Mohammed

11. Interference • Interference is caused when a strong external signal interferes with a signal. • Radio frequency interference (RFI) is aninterference caused by broadcast signals from a radio or television transmitter. • Electromagnetic interference (EMI) when motor or source of intense electrical activity creates an electromagnetic signal that interferes with a data signal. • Near end crosstalk (NEXT) and Far end crosstalk (FEXT) - interference from another data signal being transmitted on adjacent wire. Prepared by Saher H. Mohammed

12. Transmission Media • Media is the base for communication between devices. • Coaxial cables (coax). • Twisted Pair cable. • Fiber optic cables. • Wireless. Prepared by Saher H. Mohammed

13. Coaxial Cable (coax) • Coaxial cables are very common in connecting TV’s to cable services or satellite. • It is used in these areas because of its high bandwidth and shielding capabilities. • Coax cables are less prone to the external interferences, but very costly to run. Prepared by Saher H. Mohammed

14. Coaxial Cable (coax) Prepared by Saher H. Mohammed

15. Twisted-pair Cable • Twisted-pair cables have replaced the coax cables in the Ethernet networks. • Twisted-pair cables use the same technology used by the phone company for the movement of electrical signals. • Twisted-pair cables come if two forms, • Unshielded Twisted-pair cables • Shielded Twisted-pair cables Prepared by Saher H. Mohammed

16. Twisted-pair Cable • Shielded twisted-pair Cable (STP) has a foil shield around the pairs to provide extra shielding from electromagnetic interference. • Unshielded twisted-pair Cable (UTP) has no such foil around it. It uses the actual twists to eliminate interference. • STP provides better communication, but it is expensive compared to UTP. Prepared by Saher H. Mohammed

17. Twisted-pair Cable • The standard method of connecting twisted-pair cables is via a 8-pin connector called RJ-45 connector. • Twisted-pair cables are divided into three categories depending upon their transmission speed. Prepared by Saher H. Mohammed

18. Twisted-pair Cable Prepared by Saher H. Mohammed

19. Fiber Optic Cables • Fiber optic cable uses a beam of laser light to connect devices over a thin glass wire. • The biggest advantage of fiber optic cables is the higher bandwidth. These cables are used as a backbone to all the large networks and internet. • The biggest disadvantage of fiber optic cables is the cost. Prepared by Saher H. Mohammed

20. Fiber Optic Cables • Making connection to a fiber optic cable is very difficult/ impossible. • It is very difficult to splice a fiber optic. Making the precise connections on the end of fiber optic line is a highly skilled job and is done by a specifically trained professionals. • Once the connector is fitted on the end, several forms of connectors and blocks are used to make new connections. Prepared by Saher H. Mohammed

21. Fiber Optic Cable Prepared by Saher H. Mohammed

22. Fiber Optic Cable Prepared by Saher H. Mohammed

23. Unguided Media – Wireless • Transmission is sent and received through invisible waves. • Unguided media is a phrase used to cover all transmission media not guided by wire or fiber. • Unguided media includes radio frequency (RF), infrared (IR) and microwave methods. Prepared by Saher H. Mohammed

24. Unguided Media – Wireless • Unguided media have one attribute in common, that they are unguided and can travel to many machines simultaneously. • Allows the user to move freely around the office or campus and still remain connected to the network. • Fastest-growing segment of network media today. • Less expensive than copper or fiber optic lines. Prepared by Saher H. Mohammed

25. RF/Microwave • Radio Frequency (RF) is the most common and widely used method of wireless communication. • RF waves uses variety of frequency bands, each with special characteristics. • Microwave is used to describe a specific portion of the RF spectrum that is used for communication as well as other tasks such as cooking. Prepared by Saher H. Mohammed

26. RF/Microwave • Advantages of Microwaves • Microwaves can penetrate through thick walls • Microwaves can propagate through rough terrain • Microwaves have broadcast capability • Microwaves provide cost-effective solutions Prepared by Saher H. Mohammed

27. Infrared (IR) • IR is a band of electromagnetic energy just beyond the red end of the visible spectrum. • IR is commonly used in remote control devices, wireless devices like printers, keyboards, mice and PDA’s. • Drawbacks of IR • Slow • Cannot penetrate thick walls Prepared by Saher H. Mohammed

28. Network Interface Card • The NIC serves as the connection between the personal computer and the network media. • It connects to the computer on its base by plugging into an expansion slot of the computer. • Another connection is accessible from the outside of the computer and has connections for the cables to plug into the network. Prepared by Saher H. Mohammed

29. Network Interface Card Prepared by Saher H. Mohammed