1.3 The Platform for Communications

The fundamental purpose of a communications system is the exchange of data between two parties.

1. A data communications system has five key components:


Communications between two parties

	Message. The message is the information (data) to be communicated. Popular forms of information
	include text, numbers, pictures, audio, video, and other forms of communication enabled by
	the Internet.
	Sender. The sender is the device that sends the data message. It can be a computer, workstation,
	telephone handset, video camera, and so on

1.3 The Platform for Communications

	Transmission Medium. The transmission medium is the physical path by which a message travels from
	sender to receiver. Network connections can be wired or wireless. Some examples of wired media
	include twisted-pair wire, coaxial cable, and fiber-optic cable. An example of wireless media is
	radio waves.
	Receiver. The receiver accepts the signal from the transmission system and converts it into a form
	that can be handled by the destination device. For example, a modem will accept an analog signal
	coming from a network or transmission line and convert it into a digital bit stream.
	Protocol. A protocol is a set of rules that govern data communications. Rules govern every step of the
	process, from from the way cables are designed to the way the digital signals are sent. It represents an
	agreement between the communicating devices. Takes the incoming data from the receiver. Without
	a protocol, two devices may be connected but not communicating.

1.3 The Platform for Communications

2. There are two possible types of connections between the sender and the receiver:

	Point-to-Point: A point-to-point connection provides a dedicated link between two
	communicating devices.

Point-tot-point connection

Multipoint: A multipoint connection is one in which more than two specific devices share a single link.

1.3 The Platform for Communications

Multipoint connection
3. A device that provides electrical resistance at the end of a transmission line is called terminator.
     Its function is to absorb signals on the line, thereby keeping them from bouncing back and being
     received again by the network.