1. OCR AS Level F451: 3.1.5 Data transmission 3.1.5 Data transmission a. Describe the characteristics of a LAN (local area network) and a WAN (wide area network); b. Show an understanding of the hardware and software needed for a LAN and for accessing a WAN, eg the internet; c. Describe the different types of data transmission: serial and parallel; and simplex, half-duplex and duplex modes

2. a. Describe the characteristics of a LAN (local area network) and a WAN (wide area network); OCR AS Level F451: 3.1.5 Data transmission

3. What is a network? A network is a collection of two or more computers connected together to share resources. OCR AS Level F451: 3.1.5 Data transmission

4. Types of network Local Area Network (LAN) – Covers a small (local) geographical area for example a single building or a school. Your home network is a LAN. Wide Area Network (WAN) – Covers a large (wide) geographical area for example a country or a continent. The internet is a WAN. The distinction is between the geographical area NOT the number of machines. A network with 1000 clients in a single house is still a LAN because it covers a small geographical area. OCR AS Level F451: 3.1.5 Data transmission

5. b. show an understanding of the hardware and software needed for a LAN and for accessing a WAN, e.g. the internet OCR AS Level F451: 3.1.5 Data transmission

6. To build or access a network you need these things: ●At least two computers. ●A network card. ●Network cable. ●A switch or a hub to connect the cable to and exchange signals. ●On large networks with a significant amount of traffic a Network server is needed to manage data transmission. OCR AS Level F451: 3.1.5 Data transmission Accessing a network

7. c. describe the different types of data transmission: serial and parallel; and simplex, half-duplex and duplex modes; OCR AS Level F451: 3.1.5 Data transmission

8. Serial data transmission OCR AS Level F451: 3.1.5 Data transmission In serial transmission bits are sent one at a time over a single wire. The speed of transmission depends on the medium being used but could be very high (in some cases faster than a slow parallel transmission).

9. Parallel data transmission OCR AS Level F451: 3.1.5 Data transmission Parallel transmission is used inside computer systems and for very short distances (a few meters). A parallel port could send 8, 16 or 32 bits simultaneously down separate lines. Before USB parallel ports were often used to connect to printers.

10. Types of transmission Simplex data transmission– Is used for transmission of data in one direction (for example from a mouse to a computer Half duplex data transmission – Used to transmit data in both directions but not at the same time. Duplex data transmission – Is used for transmission of data in both directions simultaneously. OCR AS Level F451: 3.1.5 Data transmission