i. Differentiate between data and signals
ii. To name various components of a communication system
iii. To describe the characteristics of the effective communication
iv. To differentiate between protocol and standard
v. To know various standards organization
Data is considered to be raw data. It represents ‘values of qualitative or quantitative variables, belonging to a set of items.’ It may be in the form of numbers, letters, or a set of characters. Data is often collected via measurements. In data computing or data processing, data is represented by in a structure, such as tabular data, data tree, a data graph, etc.
Data can be analog data or digital data- analog data refers to information that is continuous, example voice, surrounding temperature, time.
Digital data take discrete values, examples being the data stored in computer in the form of 0’s and 1’s. Digital clock displays the digital information about time.
Our voice can be directly communicated as acoustic signals if the physical distance between two persons is very small. However, sound energy can travel only a small distance before it dies down. You can’t expect someone to hear your voice at a little longer distance. Also it is not possible for you to listen to something that was said by someone a few days or years back.
Thus, to communicate over longer distance we need to convert the data into signals. With the use of microphone we can convert your voice energy into the electrical wave called signals. At the other end these waves or signals are converted back into voice with the use of speakers. The use of mic and speakers covert our acoustic signal into electrical signals and then back into voice / audio. The audio signals can be stored as analog format or digital format for playing at a later time. Use of other communicating technology/devices have made it possible to transmit it to different networked systems.
Figure above shows how our voice is communicated using mic and speaker system. Voice, which is an acoustic wave is converted into electrical signal and transmitted over cables as electromagnetic signals and then again converted as the voice signal