Basic Digital Electronics

Before entering to the detailed networking topics, it is always better to start with basics of digital electronics and digital communication.

The digital electronics as the name implies is electronics of digits or digital data, whatever the data you have is not matter in this case, may be it is voice, video, image, text anything that is manipulated as digits. The digital communication thus should be the communication between digital equipments in digital form of data.

The basics of digital electronics is the binary arithmetic and logic, the binary is base 2 number system in which the possible two digits are 1 and 0, which in turn implies to the two states of electric/electronic component i.e. ON and OFF.

The usual arithmetic like +(addition) , -(subtraction), *(multiply), /(division) are also possible with binary numbers too, in addition to that in binary system we have some logical operations like AND, OR, NOT, XOR etc, for our topic, it is having much importance than other for later discussions.

And the basics of the digital circuits is based on this operations, in the form of simple electronic circuits called digital logic gates which will output the result of these logical operations. And here the output of such great operations,

The AND, OR and XOR gates have two inputs while for NOT only one input and all are having one output. Remember that in digital logic the output 1 is true and 0 is false

AND

its output is true(1) only if both of its inputs are true, all other cases it result false(0)

OR

Its output is true if any or both of the inputs is true, result is false only if both inputs are false

XOR

Its output is true if exactly one of the two inputs is true, i.e. odd number of true(1)s

NOT

It just negates or complements the input, if the input is true output will be false and if input is false output will be true

When the AND, OR, XOR combined with NOT, the output of the gates will be the opposite of the AND, OR, XOR operations and the resulting gates are NAND, NOR, XNOR respectively. Here the NAND and NOR are called universal gates and any other logic gate can be constructed using combination of any of these two gates.

So keep the operations in mind and remember these are the operation behind any digital device, whether it is computer, mobile, DVD player anything, and in the communication equipments like routers, switches, and your digital TV receiver.