Communication begins with a message, or information, that must be sent from one individual or device to another. People exchange ideas using many different communication methods. All of these methods have three elements in common:
- Message source (or sender): Message sources are people, or electronic devices, that need to send a message to other individuals or devices.
- Channel: Consists of the media that provides the pathway over which the message can travel from source to destination.
- Message Destination (or receiver): The destination receives the message and interprets it.
Click the Play button in Figure 1 to view the animation of communication between two people.
Consider, for example, the desire to communicate using words, pictures, and sounds. Each of these messages can be sent across a data or information network by first converting them into binary digits, or bits. These bits are then encoded into a signal that can be transmitted over the appropriate medium. In computer networks, the medium is usually a type of cable, or the atmosphere for a wireless transmission.
Click the Play button in Figure 2 to view the animation of communication between two devices over a network.
Note: The term network in this course refers to data or information networks capable of carrying many different types of communications, including traditional computer data, interactive voice, video, and entertainment products.