The purpose of computer networks is to enable users to manipulate data so it can be stored, retrieved, and shared. To understand how available technology enables us to do this, we need to define a few terms and understand some basic concepts. Data are entities that convey meaning. Computer data is stored as a series of electrical charges arranged in patterns to represent information. It is not the information itself.
Information means decoded data, in human-readable form.
In other words, information is the real-world, useful form of data. For example, the data in an electronic file can be decoded and displayed on a computer screen or printed onto paper as a business letter. Encoding and Decoding Data To store meaningful information as data and to retrieve the information, we use an encoding scheme we agree on a series of electrical patterns that will represent each of the discrete pieces of information we want to store and retrieve. There are many encoding schemes in use. Signals are simply the electric or electromagnetic encoding of data.