1. Additional questions about Conducted and Wireless Media School of Business Eastern Illinois University

2. 2 Conduted and Wireless Media n Why is twisted pair wire called twisted pair? Twisted pair wire often contains two or more pairs of wires. The wires in each pair are twisted around each other. n How does crosstalk occur in twisted pair wire? Electromagnetic radiation is emitted from one wire, which is picked up by a second wire. n What are Category 1, 2, 3, 4, 5 and 6 twisted pair wire used for? Cat 1: telephone lines; Cat 2: T-1 and ISDN; Cat 3, 4, 5 and 6: LANs.

3. 3 Conduted and Wireless Media n What are the advantages and disadvantages of shielded twisted pair compared to unshielded twisted pair? The main advantage is that it provides a better level of isolation from interference. The primary disadvantage is cost. n What is the primary advantage of coaxial cable compared to twisted pair? Coaxial cable has less noise and is more protected again interference. n What is the difference between Baseband coaxial and Broadband coaxial cable? Typically, baseband carries digital signals through a single transmission channel. Typically broadband carries analog or digital signals using multiple channels.

4. 4 Conduted and Wireless Media n Is Category 1 the best wire for long distance transmissions? Explain. No. Cat 1 can go 2-3 miles, but only at very low data transfer rates. n The local cable TV company is considering removing all the coaxial cable and replacing it with fiber optic cable. List the advantages and disadvantages of this plan. Higher data rates, less noise, but expensive. n The local cable TV company has changed its mind. It is now going to replace all the existing coaxial cable with unshielded twisted pair. List the advantages and disadvantages of this plan. Noise used to be a huge problem when transmitting video signals through twisted pair, but new a technology (e.g. DVS) has solve that problem.

5. 5 Conduted and Wireless Media n Why is it attractive to use a wireless LAN to connect to a wired LAN? Servers normally are on a wired LAN, and in many businesses and Schools people who are moving need to access resources on the servers. Connecting a Wireless LAN to a wired LAN make it possible to access these resources. n Can we implement a completely wireless LAN not connected to a Wired LAN? Explain. Yes. Using a switch with built-in Access Point, we can implement a Wireless LAN not connected to a Wired LAN. We can even implement a small completely wireless LAN without Access Point or Switch. In this case, Wireless NICs operate automatically in ad hoc mode, in which they talk directly to other wireless stations. This only works for small LANs. See next slide for illustration.

6. 6 Ad Hoc 802.11 Wireless LAN n No Access Points are used – All stations must be Wireless (Wireless NICs) – Stations broadcast to one another directly – Not scalable but can be useful for SOHO use