7.1 The Physical Layer - Communication Signals

Signals can be analog (Figure 1-1) or digital (Figure 1-2).


Figure 1-1: An example of an analog signal


Figure 1-1: An example of an analog signal

7.1 The Physical Layer - Communication Signals

	Digital signals have discrete values while analog signals have continuous values with time.
	Signals inside the computers are digital but on the communication media can be analog or digital.
	One of the most important functions of the physical layer is encoding the data and taking care of transmitting/receiving it over the communication media.
	Other functions of the physical layer include defining the hardware/software specifications of the cables, connectors, network interface cards, and other hardware devices.