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Data encoding: refers to transforming data into a specific format for efficient transmission or storage.
- Essential for avoiding errors in data transmission.
Transmission errors: can occur during this process, causing data corruption.

Random errors: Occur due to noise or interference in the transmission medium.
Burst errors: Failures that affect a sequence of bits, leading to multiple errors in a short time span.

Parity Bit: A simple error detection method that adds a single bit to binary data. If the total number of 1s is odd, the parity bit is set to 1 (odd parity); if even, it is set to 0 (even parity).
- Limitation: Cannot detect an even number of bit errors.
Checksum: Involves summing binary values and sending the sum with the data. The receiver calculates the checksum of the received data and compares it to the transmitted one.
- Limitation: Cannot identify which part of the data is erroneous.
Cyclic Redundancy Check (CRC): A more advanced method that uses polynomial division to produce a checksum.
- Benefits: Detects errors in larger data blocks and identifies specific errors effectively.

Automatic Repeat reQuest (ARQ): A protocol for error correction whereby the receiver requests retransmission of corrupted data.
- Variants include Stop-and-Wait ARQ and Sliding Window ARQ for efficiency.
Forward Error Correction (FEC): Messages are encoded before transmission. The sender adds redundant data to enable the receiver to detect and correct errors without needing retransmission.

Essential in digital communication and data storage systems to ensure accuracy and reliability in data transmission.

Used in various applications such as TCP/IP networks, data storage devices, and video transmission to maintain data integrity across communication channels.