Analog and Digital Signals:

Communication systems that transmit data by means of electrical signals may use either digital or analog signals.

Analog Signal:

In this type of transmission, analog signals are transmitted in continuous form and can be represented in sine waves. Telephone line, FM radio music, TV transmission are the examples of analog signals.

Digital Signals:

In this type of transmission data flow is in the form of bits (0,1). 0 means absence of current and 1 means presence of current. Only two amplitudes are possible in this i.e high amplitude means 1, low amplitude means 0. These signals are discrete in nature. Quality of digital transmission is better than analog transmission. Modern computer are digital machines. Hence, the data transmission between computer peripheral and inner parts of computer is digital transmission. For example: Pen drive to hard disk, DVD-ROM to pen drive, RAM to microprocessor and ADSL modem to your computer are the common example of digital single transmission.

Transmission Media (Communication Media)

Every network is created with the help of a transmission media. The communication channel is the medium through data is exchanged between the computers in a network. Transmission media generate the pathway between sender and receiver.

Types of Transmission media:

Transmission media are basically classified into two types. They are as follows:

1. Guided/Bounded/Wired communication media
2. Unguided/Unbounded/ Wireless communication media