Longitudinal Redundancy Check


The Longitudinal Redundancy Check (LRC) is a form of error detection method used in digital communications to ensure data integrity. It is achieved by creating a separate block of data, known as a checksum, from the set of data being transmitted. The receiver then calculates the checksum and compares it with the transmitted one to detect errors.


The phonetic pronunciation of Longitudinal Redundancy Check would be: Lon-ji-too-din-al Re-dun-dan-see Check

Key Takeaways

  1. Function: The Longitudinal Redundancy Check (LRC) is a form of redundancy check that is applied to a stream of data words to ensure that the data hasn’t been corrupted while being transferred. It helps detect errors in the data transmission process.
  2. Calculation: LRC is computed by performing a bitwise exclusive OR (XOR) operation on a succession of data words. This mechanism counts the number of 1-bits in each positional column of the data block to generate the checksum, which is then sent along with the data.
  3. Limitations: Despite being a useful error detection tool, LRC has its limitations. It’s not a completely foolproof method, as identical errors in the same position of two separate data words could escape detection.


Longitudinal Redundancy Check (LRC) is a significant concept in computing and technology because it plays a crucial role in error detection while transmitting or storing digital data. LRC is an error-checking method that adds an extra byte of data to a block of data to ensure its integrity during transmission or storage. If the data is altered during these processes, the LRC value will change, signaling that an error has occurred. Therefore, ensuring the correct transmission or storage of digital data and preserving the integrity and reliability of digital information predominantly depends on techniques like LRC. This technique is especially critical in fields where data integrity and reliability are paramount, such as telecommunications, computing, and information technology.


The Longitudinal Redundancy Check (LRC) is a form of error checking technology that plays a vital role in maintaining data integrity during transmission in a communication system. Reviewing the data accuracy is its key functionality. It helps detect errors in sent messages, which can be caused by factors such as interference or noise. By adding an extra data byte, known as a parity byte at the end of each message, it checks whether the data has been transmitted correctly or not.This method of error detection is employed in many sectors to ensure reliable data transmission. For instance, in computer networks where packets of data are sent from one place to another, LRC ensures that all the information reaches the destination without loss or alteration. Additionally, in sectors like banking, LRC is also used in magnetic stripe cards (like debit and credit cards) to verify the accuracy of the data stored in it. Thus, through the use of LRC, the occurrence of any potential errors can be addressed and further complications can be prevented.


1. Data Communication Networks: In real-world computer networks, Longitudinal Redundancy Check (LRC) is often used to detect errors that may occur during data transmission. Networks like the Ethernet LAN or WAN networks make use of this technology to verify the integrity of packets that are sent over the network.2. Serial Communication: Used extensively in embedded systems where data transmission over serial ports takes place. For instance, in RS232 (standard for serial communication transmission of data), LRC is used to check for errors in the data packets that are sent and received.3. Magnetic Stripe Cards: LRC is frequently used in the financial sector to ensure the validity of data on Magnetic Stripe Cards (like credit and debit cards). The LRC value is stored in the card and checked at each transaction point to identify any errors in the important data stored on these cards.

Frequently Asked Questions(FAQ)

**Q1: What is Longitudinal Redundancy Check (LRC)?**A1: Longitudinal Redundancy Check (LRC) is a form of error detection commonly used in digital data storage and transmission. It involves computing a checksum based on each bit position’s parity, rather than the entire message, to identify potential errors.**Q2: How does Longitudinal Redundancy Check work?**A2: LRC works by taking the exclusive OR (XOR) of all the words (typically bytes) in the data block. In simpler terms, it calculates each data block’s parity bit and adds an additional block, the LRC, containing parity information for redundancy.**Q3: Where is LRC typically used?**A3: It is generally used in data storage and telecommunication systems to detect and possibly correct errors during data transmission.**Q4: What are the advantages of using Longitudinal Redundancy Check?**A4: LRC is known for its simplicity, ease of implementation, and the ability to detect most common errors that may occur during data transmission, such as single-bit and two-bit errors.**Q5: Can LRC detect all types of errors?**A5: While LRC can detect many basic error types, it is not foolproof. It may not detect errors that alter an even number of bits or if the entire data block is lost during transmission.**Q6: What is the difference between LRC and other error-detecting codes?**A6: The primary difference lies in how the check value is computed. LRC calculates the parity of each bit position, while others such as Cyclic Redundancy Check (CRC) and Checksum might use different methods such as polynomial division or summation, respectively.**Q7: Is an LRC a type of parity check?**A7: Yes, a Longitudinal Redundancy Check is a type of parity check, specifically a form of vertical parity check, where parity bits are calculated along the length (vertically) of the data. **Q8: How to calculate the LRC?**A8: For each column of bits (usually organized in bytes), calculate the parity bit (1 if the total number of ‘1’s is odd, 0 if even). Put these parity bits together to form the LRC byte.

Related Tech Terms


  • Error Detection
  • Data Transmission
  • Checksum Algorithm
  • Parity Bit
  • Binary Data


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