Data exchange 2

Data exchange 2

1. Transmission modes

   • Simplex transmission
     • Sends data in one direction only. A radio broadcast is a good example of this transmission.
   • Half- duplex transmission
     • This allows two way transmissions but the devices don't transmit at the same time. this is a system that controls and monitors the manufacturing processes.
   • Full- duplex transmission
     • Allows two way communication at the same time. The telephone system, land or mobile is an example of this transmission.

2. Parallel transmission

   • A number of bits of data that transmits over an equal number of wires and channels. This allows the bits in a whole bytes of information to be transfered together.

3. Serial transmission

   • Bits are transmitted one at a time over a single wire or channel. this reduces the cost of the cable, but gives a slower rate of transfer.

4. Universal serial bus

   • Is a serial transmission method which was introduced to make many of the connections to the computer look the same. Nowadays USBs are used in a wide variety of devices, such as mobile phones, memory cards etc.

5. Bi- directional transmission

   • This has several meanings within the data communications, but it is essentially about transmitting in both directions.

6. Client- side processing

   • Is the use of a scripting language to create codes on webpages which provides interactivity. The important point is that the interaction takes place within the webpages and the code is downloaded to the user's computer when the webpage is opened by the user's browser.
   • Benefits of Client- side processing
     • Speed: The interaction may be faster once the code has been downloaded within the page. Security: It is the most secure as all the action takes place in the downloaded page and nothing will come from the browser.
   • Disadvantages
     • It is browser specifics: Not all the scripts work in the same way on all the browsers, so you may have to create different versions depending on the brower used. Computer Speed: It can be effected by the speed of your own computer. As all of the activity is being placed on the downloaded webpage, the speed of the download and the speed of the processing.

7. Server side processing

   • Involves the scripts which reside and are running on another computer on the internet (web server).