1. Amandeep Singh Computer Science Department,PCTE

2. Transmission Media Guided Media Unguided Media WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

3. Figure 7-2 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

4. Figure 7-3 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

5. Twisted-Pair Cable Figure 7-4 and 7-5 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

6. Effect of Noise on Parallel Lines Figure 7-6 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

7. Noise on Twisted-Pair Lines Figure 7-7 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

8. Twisted-Pair Cable Figure 7-4 and 7-5 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 The bandwidth depends on the thickness of the wire and the distance traveled, but several megabits/sec can be achieved for a few kilometers in many cases Category 3 twisted pairs consist of two insulated wires gently twisted together the more advanced category 5 twisted pairs were introduced with more twists which results in less crosstalk and a better-quality signal over longer distances

9. Twisted-Pair Cable Figure 7-4 and 7-5 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 A twisted pair consists of two insulated copper wires, typically about 1 mm thick. Twisting is done because two parallel wires constitute a fine antenna. When the wires are twisted, the waves from different twists cancel out Twisted pairs can run several kilometers without amplification, but for longer distances, repeaters are needed Twisted pairs can be used for transmitting either analog or digital signals The bandwidth depends on the thickness of the wire and the distance traveled, but several megabits/sec can be achieved for a few kilometers in many cases Category 3 twisted pairs consist of two insulated wires gently twisted together the more advanced category 5 twisted pairs were introduced with more twists

10. Unshielded Twisted-Pair Cable Figure 7-8 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

11. UTP Connectors Figure 7-9 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

12. Shielded Twisted-Pair Cable Figure 7-10 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

13. Coaxial Cable Figure 7-11 and 7-12 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 A coaxial cable consists of a stiff copper wire as the core, surrounded by an insulating material. The insulator is encased by a cylindrical conductor, often as a closely-woven braided mesh. The outer conductor is covered in a protective plastic sheath.

14. Figure 7-11 and 7-12 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 Coaxial Cable It has better shielding than twisted pairs, so it can span longer distances at higher speeds. Two kinds of coaxial cable are widely used. One kind, 50-ohm cable, is commonly used when it is intended for digital transmission from the start. The other kind, 75-ohm cable, is commonly used for analog transmission and cable television

15. Fiber Optics cable Figure 7-20 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

16. Refraction Figure 7-13 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

17. Fiber Optics cable Figure 7-20 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 An optical transmission system has three key components: the light source, the transmission medium, and the detector. A pulse of light indicates a 1 bit and the absence of light indicates a 0 bit.

18. Figure 7-16 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

19. Multimode Step-Index Figure 7-17 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

20. Multimode Graded-Index Figure 7-18 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

21. Single Mode Figure 7-19 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998

22. Transmission Impairments Attenuation Means loss of energy or signals. Distortion means change in signal due to long distance travellings. Noise is interference of other sources such as Thermal noise, Crosstalk noise Induces noise from appliances and motors which act as anttena Impulse noise comes from lightening and power lines and vehicles.