Introduction
The data must be in distinct digital form for a computer to utilize it. Signals, like data, may have both analog and digital forms. Data must first be transformed into digital form before being sent digitally. The computer can only interpret binary language, expressed in the form of 0 or 1, and it also stores data in digital form.
As a result, we must transform the data into a digital format that the computer can understand. Data can be represented in two forms either analog or digital.
Following are the conversion techniques used for data conversion:
 Analog to digital conversion
 Analog to analog conversion
 Digital to digital conversion
 Digital to analog conversion
We need to convert our data to a digital format to store it on a computer. There are only two methods to convert data into digital form and in this blog, we'll go through digitaltodigital conversion.
DigitalToDigital Conversion
This section describes how to transform digital data into digital signals. There are two methods to accomplish it: line coding and block coding. Line coding is required for all communications, but block coding is optional. The representation of digital information by a digital signal is known as digitaltodigital encoding. The process of converting binary 1s and 0s created by a computer into a series of voltage pulses sent across a wire is known as digitaltodigital encoding.
The following are three approaches employed in this conversion:
 Line Coding
 Block Coding
 Scrambling
Line Coding
The technique of converting digital data into digital signals is called line coding. The most frequent kind of digital data is binary data. It is internally represented (stored) as 1s and 0s. Assume the data is in text, numbers, audio, or video and is stored as a sequence of bits in the computer. Line coding converts a sequence of bits into a digital signal.
On the transmitter side, digital data is encoded into digital signals, and digital data is recreated on the reception side by decoding the digital signal.
Line Coding can be broadly classified into five categories:
 Unipolar
 Polar
 Bipolar
 Multilevel

Multi Transition
Unipolar
Unipolar encoding techniques encode data with a single voltage level. In this scenario, high voltage is delivered to represent binary 1 while no voltage is transmitted to represent binary 0. Because there is no rest condition, it is also known as UnipolarNonreturntozero. It either represents 1 or 0.
Polar
In this line scheme, the voltages are on both sides of the time axis. Consider the following illustration: the level of 0's voltage may be positive, whereas the voltage level can be negative. As a result, we employ two voltage amplitude levels in Polar NRZ encoding.
Polar NRZ is of two types:
 NRZL(NRZlevel): The voltage level is most responsible for the bit's value. As a consequence, the bit value determines the signal's level.
 NRZI(NRZInvert): The bit's value is largely affected by the voltage level change. The bit is 0 if there is no change; if there is a change, the bit will be 1.
There will be no inversion in the above figure if the next bit is 0. However, if the following bit is 1, inversion will occur.
Bipolar
There are three voltage levels in the Bipolar scheme: positive, zero, and negative. One data element's voltage level is set to 0, while the voltage levels of other data elements alternate between positive and negative.

Multilevel Scheme
The mBnL (Multilevel Coding) system is another name for the scheme.
m > The length of the Binary pattern.
B > The binary data.
n > The length of the signal pattern.
L > The number of levels in the signaling.
This scheme is available in three separate versions:
→ 2B1Q
→ 8B6T
→ 4DPAM5

Multi Transition
This approach requires three levels (+V, 0) and more than three transition rules to travel between the levels.
The following are the rules:
→ There is no transition if the next bit is 0.
→ The next level will be 0 if the next bit is 1 and the current level is not 0.
→ The next level is the inverse of the previous nonzero level if the next bit is 1 and the current level is 0.
→ For lengthy 0s, this approach does not do selfsynchronization.
Block Coding
Redundant bits are utilized to guarantee that the received data frame is accurate. In evenparity, for example, one parity bit is inserted to make the frame's count of 1s even. The initial number of bits is raised in this manner. It's known as Block Coding.
Slash notation, mB/nB, is used to indicate block coding.
Where n > m, an nbit block replaces an mbit block. Three stages are involved in block coding:
 Division
 Substitution
 Combination
It is then linecoded for transmission when block coding is completed.
Also see, Personal Area Network
Scrambling
By introducing scrambling, we may change the line and block coding. It's worth noting that scrambling, as opposed to block coding, is mostly done during the encoding process.
The two most frequent scrambling strategies are listed below:

B8ZS (Bipolar with 8zero substitution): In this method, the sequence 000VB0VB is used to substitute eight successive zerolevel voltages. V stands for violation in this sequence, a nonzero voltage that breaks the AMI encoding rule. ACCORDING TO THE AMI RULE, the B in the above sequence denotes Bipolar, which essentially means nonzero voltage level.
 HDB3 (HighDensity Bipolar 3zero): This method is more careful than B8ZS since it replaces four consecutive zerolevel voltages with a sequence of 000V or B00V. The main reason for utilizing two different replacements is to maintain an equal number of nonzero pulses following each one. For this aim, there are two guidelines to follow: 1. If the number of nonzero pulses following the preceding replacement is odd, we'll use the 000V substitution pattern to level things out. 2. If the total number of nonzero pulses after the preceding replacement is even, we'll use the B00V substitution pattern to equalize the total number of nonzero pulses.
Check out this problem  Count Inversions and Basic Networking Commands
You can read related articles such as Congestion Control in Computer Networks here.