1. Prepared by Engr.Jawad Ali BSc(Hons)Computer Systems Engineering University of Engineering and Technology Peshawar

2. Transmission Medium  A transmission medium can be broadly defined as anything that can carry information from a source to a destination.

3. Classes of transmission media

4. Twisted pair  A twisted pair consists of two conductors (normally copper), each with its own plastic insulation, twisted together, as shown

5. Twisted cable (cont)  One of the wires is used to carry signals to the receiver, and the other is used only as a ground reference. The receiver uses the difference between the two.  the number of twists per unit of length (e.g., inch) has some effect on the quality of the cable.

6. Twisted pair(cont)  Twisted pair cables are divided in two parts  Unshielded twisted pair(UTP)  Shielded twisted pair(STP)

7. STP  There is metal casing around STP, which improves the quality of cable by preventing the penetration of noise or cross talk.  STP is bulkier and more expensive.

8. UTP categories  EIA has developed standards to classify UTP into 7 categories, with 1 is the lowest and 7 is the highest quality.

9. UTP connectors  The most common UTP connector is RJ45 (RJ stands for registered jack), as shown

10. Coaxial cable

11. Incomplete