The Internet and Communications

The Internet and Communications

1. Common File Standards

   • MP3
     • stores compressed audio
     • uses lossy compression
     • quick download speeds
     • maintain reasonable quality
   • .JPG
     • Stores compressed images
     • uses lossy compression
     • uses lossy compression
     • reasonably good quality
   • .PNG
     • uses lossless compression
     • excellent picture quality
   • .FLA
     • stored flash multimedia
       • interactive games
       • videos
       • music
   • HTML
     • used for making webpages

2. Compression

   • Lossless Compression
     • Pros
       • There is no loss of detail
       • The file size is smaller
     • How does it work
       • uses an algorithm
       • replaces a common string with a token
   • Lossy compression
     • Pros
       • the file size is smaller
     • Cons
       • Data is lost
       • The quality is worse
     • How does it work
       • it discards some of the data

3. The Internet

   • Necessary Hardware
     • Modem
       • allows computer systems to communicate over analogue systems
         • analogue systems e.g. telephone network
     • Broadband Modems
       • Allows for faster data transfer
       • can make telephone calls over the same line at the same time
     • Media Converter
       • connect to the internet using fibre optic cables

4. Routing

   • Definition
     • the method of selecting paths along which packets are sent on a computer network