The study assesses a brain–computer interface (BCI) that utilizes the P300 component of the event-related potential (ERP) to communicate letters to a computer. The system presents a 6x6 matrix of letters, and the user focuses on the letter they wish to communicate while the rows and columns are intensified in a random sequence. The rare events in the oddball paradigm elicit a P300, which the computer detects to determine the transmitted character. The study reports that an offline version of the system can communicate at a rate of 7.8 characters per minute with 80% accuracy. Real-time performance was also evaluated, showing a communication speed of 4.8 characters per minute at 90% accuracy. The study concludes that a P300-based BCI is feasible and practical, but further research is needed to improve communication speed and accuracy, especially for disabled individuals.The study assesses a brain–computer interface (BCI) that utilizes the P300 component of the event-related potential (ERP) to communicate letters to a computer. The system presents a 6x6 matrix of letters, and the user focuses on the letter they wish to communicate while the rows and columns are intensified in a random sequence. The rare events in the oddball paradigm elicit a P300, which the computer detects to determine the transmitted character. The study reports that an offline version of the system can communicate at a rate of 7.8 characters per minute with 80% accuracy. Real-time performance was also evaluated, showing a communication speed of 4.8 characters per minute at 90% accuracy. The study concludes that a P300-based BCI is feasible and practical, but further research is needed to improve communication speed and accuracy, especially for disabled individuals.