Transmission of data

Transmission of data

1. Parallel transmission A number of bits of data are transmitted simultaneously over an equal number of channels It has a very short range

2. Serial Transmission Bits are transmitted one at a time over a single channel. This reduces the cost of cable, but makes data transmission slower. Also more complex, as bytes have to be disassembled into individual bits before transmission and reassembled after. Can be used over longer distances.

3. USB Universal Serial Bus is a serial transmission method introduced to make computer connections consistent

4. Bi-directional Transmission Transmitting in 2 directions. Fibre-Optics – light passes in one direction only, so extra fibres are added to the bundle to carry the signal in the opposite direction.

5. Simplex Transmission Sends data in one direction only Example: A radiobroadcast TV remote controlee

6. Half-duplex transmission Allows 2 way communication, although only one at a time Example: Sends a message

7. Full-duplex transmission Allows 2 way communication at the same time. Example: Telephone system

8. The use of a scripting language to create code that provides interactivity on webpages Interaction takes place within the webpage and the code is downloaded to the users computer when the webpage is opened by the users browser. Example: A rollover image on a website Code is triggered when you move the move over a part of the webpage. Benefits: Speed: Faster as code has been downloaded with the page Security: More secure as all the action takes place on the page Disadvantages: Browser specific: Not all scripts work the same way on all browsers, so you have to create different versions Computer Speed: Can affect the speed of your computer as all the activity is taking place on a downloaded webpage.

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