2. Linking Computers

 

Transmission Media

To connect computers together and transmit data LAN's use either cables or wireless transmission. They also need a Network interface Card (NIC) to link them into the cable or wireless network.

 

Cables

 

You need to know about the two main types of media: copper cabling and fibre optic cabling.

1. Copper Cabling

Coaxial cabling - this is cabling where the central cable that carries the data is surrounded by a shield of copper braiding. This protects it from interference and so coaxial cabling is found in networks in places like factories, where there can be a lot of electrical interference.

 

 

 

 

Twisted Pair Cabling - This type is used in most LAN's and is used in the school LAN. It is a simple type of cabling made up of two copper cables. It is cheap and can support quite high transmission speeds, for example over 100Mbits per second.

 

 

 

 

2. Fibre Optic Cabling

Fibre optic cabling is made up of fine strands of glass that carry pulses of light. These pulses of light represent the data being transmitted.

The advantages of fibre optic cable are that it:-

1. Is more difficult to break into the cable and so is more secure.
2. Does not suffer from electromagnetic interference (interference generated by ALL electrical equipment)
3. Can carry data at very high speeds.

The disadvantage is that it is expensive to buy and install than other types of cabling.

 

Wireless Networking

Some networks use wireless connections to transmit their data. Wireless networking transmits data through the sire using radio waves and microwave frequency radiation.

The advantages of this approach are that it:-

1. Is relatively easy to install. All you need is a transmitter/receiver and a wireless NIC on each computer on the network.
2. There is no need for any wiring.
3. Transmission speeds are very fast.

The disadvantage is that security can be a problem because wireless networks are relatively easy to hack into.

 

Network Interface Cards (NIC)

Carries out tasks vital to connect your computer to a network.

1. Takes the data sent by your computer on the network, stores it in its own memory locations and then adapts to make sure that it follows the communication rules that govern the network.
2. Takes the data coming in from the network and passes it onto the computer's processor.

Every device connected to a LAN needs a NIC, for example, computer, printer and scanner.

 

Client/Server Networks

Lots of networks are set up as a client/server networks. A client is a workstation on the network. A server is central to this set up. It is a computer that has a fast processor and lots of memory and is used to control the resources that the client workstations can use. A server can be used for a range of tasks. They might be:-

1. Organising the printing on a network (print server)
2. Holding all the data files or applications software.
3. Organising the clients' access to the internet.

 

 

 

What you have to do!

Answer the following questions under a heading "Networks" either in your "Brain" or a new Word document.

1. List two commonly used types of network cable.
2. Why is wireless networking becoming popular?
3. Why do computers that are attached to a LAN need a NIC?
4. What is the key role of a server on a client/server network?
5. What is a client?

 

What you should be able to do!

1. Describe the different methods of connecting computers together.

2. Explain why wireless networks are becoming so popular.

3. Explain what a Server does in a Client/Server network

4. Explain why computers need a NIC card.

 

Continue to 3. Multi Access