CHANNELS

Digital Channel – A communications path that handles only digital signals.

Analog Channel – A channel that carries voice or video in analog form as a varying range of electrical frequencies.

Multiplexed Channel – Multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share expensive resource.

Simplex Communication – Is a communication channel that sends information in one direction only.

Duplex Communication Is a point-to-point system composed of two connected parties or devices that can communicate with one another in both directions.

Half-duplex Communication – Provides communication in both directions but only one direction at a time.

Broadcasting Channel – Is a downlink channel used by the base stations to provide signaling information to the mobile stations.

Unicast Channel – Unicast transmission is the sending of messages to a single network destination identified by a unique address.

Multicast Channel – One-to-many or many-to-many distribution. This is a group communication where information is addressed to a group of destination computers simultaneously.

Uplink – Also known as “upstream”. This refers to the direction in which data can be transferred from the client to the server (uploading).

Downlink – Also known as “downstream”. This refers to the direction in which data can be transferred from the server to the client (downloading).

Transmission Medium – Is a material substance (solid, liquid, gas or plasma) that can propagate energy waves.

FORMATS

‘Format’ is how information or data is arranged either on a page (‘page format’) or in a file ‘file format’.

There are thousands of file formats in common use, and you recognize them by their extension. For example:

  • myfile.doc – Word
  • myfile.xls – Excel
  • myfile.ppt – Powerpoint
  • myfile.jpg – Image format
  • myfile.psd – Photoshop
  • myfile.mp3 – Sound file

‘To format a hard disk’ means that the hard disk is set up ready for writing. What actually happens is that magnetic sectors are prepared on the disk surface and hidden system files are loaded, ready for storing files. You often have to ‘format’ a storage device ready for use.

 

Source: Adapted from group presentations; http://www.teach-ict.com/glossary/F/format.htm