1. 7.1 Chapter 7 Transmission Media Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. 7.2 Figure 7.1 Transmission medium and physical layer

3. 7.3 Figure 7.2 Classes of transmission media

4. 7.4 7-1 GUIDED MEDIA Guided media, which are those that provide a conduit from one device to another, include twisted-pair cable, coaxial cable, and fiber-optic cable. Twisted-Pair Cable Coaxial Cable Fiber-Optic Cable Topics discussed in this section:

5. 7.5 Figure 7.3 Twisted-pair cable

6. 7.6 Figure 7.4 UTP and STP cables

7. 7.7 Table 7.1 Categories of unshielded twisted-pair cables

8. 7.8 Figure 7.5 UTP connector

9. 7.9 Figure 7.7 Coaxial cable

10. 7.10 Table 7.2 Categories of coaxial cables

11. 7.11 Figure 7.8 BNC connectors

12. 7.12 Figure 7.10 Fiber optics: Bending of light ray

13. 7.13 Figure 7.11 Optical fiber

14. 7.14 Figure 7.12 Propagation modes

15. 7.15 Figure 7.13 Modes

16. 7.16 Figure 7.14 Fiber construction

17. 7.17 Figure 7.15 Fiber-optic cable connectors

18. 7.18 7-2 UNGUIDED MEDIA: WIRELESS Unguided media transport electromagnetic waves without using a physical conductor. This type of communication is often referred to as wireless communication. Radio Waves Microwaves Infrared Topics discussed in this section:

19. 7.19 Figure 7.17 Electromagnetic spectrum for wireless communication

20. 7.20 Figure 7.18 Propagation methods

21. 7.21 Table 7.4 Bands

22. 7.22 Figure 7.19 Wireless transmission waves

23. 7.23 Radio Wave Transmission System Radio waves have frequencies between 10 kHz and 1 Ghz Radio waves have frequencies between 10 kHz and 1 Ghz Radio waves used for following Application Radio waves used for following Application AM radio AM radio FM radio and TV FM radio and TV Wireless LAN Wireless LAN RF bands are Licensed and Unlicenced RF bands are Licensed and Unlicenced Radio waves can brodcast omnidirectionally or directionally Radio waves can brodcast omnidirectionally or directionally

24. 7.24 Figure 7.20 Omnidirectional antenna

25. 7.25 Microwave Transmission System Microwaves have frequencies between 1 GHz to 300 Ghz Microwaves have frequencies between 1 GHz to 300 Ghz Micro waves used for following Application Micro waves used for following Application AM radio AM radio FM radio and TV FM radio and TV Wireless LAN Wireless LAN Microwaves are basically unidirectional Microwaves are basically unidirectional Microwave propogation is Line of sight propogation Microwave propogation is Line of sight propogation It support high data rate due to high fre band It support high data rate due to high fre band There are two types There are two types1]Terrestrial2]Satellite

26. 7.26 Figure 7.21 Unidirectional antennas

27. 7.27 These system use directional parabolic antennas to transmit and receive signals These system use directional parabolic antennas to transmit and receive signals Signals are highly focused and physical path must be line of sight Signals are highly focused and physical path must be line of sight Freq range used is from 4-6 Ghz and 21-23 Ghz Freq range used is from 4-6 Ghz and 21-23 Ghz Bandwidth from 1 to 10mbps Bandwidth from 1 to 10mbps Line of sight requirement make installation difficult Line of sight requirement make installation difficult The signals are affected by EMI,Jamming. The signals are affected by EMI,Jamming. Short distance can be inexpensive but long distance are relatively expensive Short distance can be inexpensive but long distance are relatively expensive Terrestrial Microwave

28. 7.28

29. 7.29 - An earth station transmits information signal to the satellite using a highly directional dish antenna. -It receives signal from one earth station,amplifies it improves the signal quality and radiate back to earth station -The receiving earth station will receive this signal using parabolic dish antennas pointed towards the satellite -The signal which is being transmitted upwards to the satellite is called as the “up link' and at freq of 6 GZ Satellite communication

30. 7.30 The signal which is transmitted back to the receiving earth station is called as the “down link” and at frq 4 Ghz Satellite receive,process,transmit the signal using transponder-2 sets-each having 12 of band 36 Mhz Satellite receive,process,transmit the signal using transponder-2 sets-each having 12 of band 36 Mhz These are typical band of freq These are typical band of freq C band=4/6 Ghz C band=4/6 Ghz Ku band:11/14GHz Ku band:11/14GHz Ka band=20/30 Ghz Ka band=20/30 Ghz Multiple Acess method such as Multiple Acess method such as Satellite communication

31. 7.31 -FDMA,TDMA,CDMA used to allow the acess of a satellite -The power requirment of a satellite is-solar panels and a set of nickel cadmium batteries,carried by the satellite itself

32. 7.32

33. 7.33 Infrared waves -The electromagnetic waves having frequencies from 300 Ghz to 400 Thz are known as infrared waves -IR uses Line of sight propogation -It cannot penetrate walls -much reduced interference and possibility of reuse same freq band in different rooms -IR waves have very large bandwidth -Sun generates radiation in the infrared bandcause interference to IR They may be used in deveploment of very high speed wireless LAN in future. -FCC licence is not required to use it.