Magnetic Stripe LRC Modification for Reader Error Prevention

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Solution Overview

Problem

Certain magnetic stripe readers experience errors when encountering specific Longitudinal Redundancy Check (LRC) characters, leading to incorrect interpretation and rejection of magnetic stripe messages, which affects the reliability of data transmission in payment systems.

Innovation Solution

A processor modifies LRC characters in magnetic stripe messages to avoid known problematic values, ensuring that the modified LRC characters do not match exceptions, thereby increasing the likelihood of successful data transmission by recalculating the LRC values and verifying they do not cause errors in magnetic stripe readers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard LRC characters are used in magnetic stripe messages, then data transmission follows conventional protocols, but errors occur in magnetic stripe readers when encountering specific LRC characters

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidreader errors caused by problematic LRC characters

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the LRC character values in magnetic stripe messages to avoid specific problematic values that cause errors in certain magnetic stripe readers. By changing the parameter values of LRC characters from standard conventions to non-problematic alternatives, the system maintains data integrity while avoiding reader failures.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent proactively identifies and avoids problematic LRC character values before they can cause errors. By预先 modifying the LRC characters to exclude known problematic values, the system prevents potential reading errors and rejections before they occur during the data transmission process.

Inventive Principle:

Principle #9Preliminary anti-action

2Adaptability or versatility

If LRC characters are modified to avoid problematic values, then reader compatibility improves, but data integrity must be maintained through proper recalculation

Engineering Contradiction:

Improvecompatibility with magnetic stripe readersVSAvoiddata accuracy in magnetic stripe messages

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the system recalculates the LRC values after modification to ensure they remain valid checksums for the altered data. This feedback loop verifies that modified LRC characters correctly represent the changed message content, maintaining data integrity while achieving reader compatibility.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system carefully adjusts LRC character parameters to non-problematic values while maintaining the mathematical relationship between the message data and its checksum. The modification process ensures that LRC values are changed in a controlled manner that preserves the error-detection functionality while avoiding reader-specific issues.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enhances the reliability of data transmission by preventing errors in magnetic stripe readers, ensuring that magnetic stripe messages are correctly interpreted and processed, thereby improving the functionality of payment systems.

Implementation Method 1

A magnetic encoder may change the information located on a magnetic medium such that a magnetic stripe reader may read changed magnetic information from the magnetic medium

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 2

A magnetic emulator may generate electromagnetic fields that directly communicate data to a magnetic stripe reader

Methodology Applied

Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Implementation Method 3

Data may be programmed onto the magnetic stripe by a magnetic stripe writer that records information onto the magnetic stripe by altering the magnetism of particles (e.g., iron-based particles) distributed along the magnetic stripe

Methodology Applied

Scientific EffectMagnetism: Magnetism

Data Source

PatentUS10169693B1Data modification for magnetic cards and devices

Publication Date: 2019.01.01 DYNAMICS INC

AI summary

Programming fixtures are provided that program devices, such as payment cards, with data, such as personal data, using light transmitters and receivers for powered cards, or using magnetic write heads for non-powered cards. A processor within the powered card computes a magnetic stripe message and associated longitudinal redundancy check (LRC) value based upon the personal data. The processor compares the LRC value against a list of LRC exceptions and changes the magnetic stripe message to change the LRC value based upon a positive comparison. A programming fixture may compute the magnetic stripe message and may change the magnetic stripe message before writing the magnetic stripe message to a static magnetic stripe upon a detection that the associated LRC value matches an LRC exception.