Information Coding System

  • Check Digit

    • Simpler form of a checksum.

    • Adds a single digit to the data.

    • Efficient but limited in error detection.

  • Checksum

    • A value added to data, calculated using an algorithm.

    • Detects errors but cannot correct them.

    • Efficiency depends on the algorithm used.

  • Majority Voting

    • Each bit is transmitted multiple times.

    • Detects and corrects errors based on the most common value.

    • Inefficient due to increased data size.

  • Parity Bit

    • A single bit added to data to check for errors.

    • Two types: Even parity (even number of 1s) and Odd parity (odd number of 1s).

    • Cannot detect errors when an even number of bits are changed.

  • ASCII

    • Stands for American Standard Code for Information Interchange.

    • Uses 7 bits to represent 128 characters (A-Z, a-z, 0-9, and symbols).

  • Unicode

    • Developed to represent a wide range of alphabets (e.g., Arabic, Greek, Cyrillic).

    • Uses 8 to 48 bits (1 to 6 bytes) per character.

  • Character Code

    • A number assigned to a character.

    • Example: A = 1, B = 2, etc.

    • Can be converted to binary for computer use.

  • Even Parity

    • Ensures the total number of 1s in the data is even.

  • Odd Parity

    • Ensures the total number of 1s in the data is odd.

  • Error Checking

    • Identifies errors in data transmission.

  • Error Correction

    • Fixes detected errors without retransmitting data.