Check characters are optional for Interleaved 2 of 5 and can be added one character, which are calculated values used to verify the integrity of the data. Disable: The scanner transmits Interleaved 2 of 5 barcodes as it is. Do Not Transmit Check Characters After Verification: The scanner checks the integrity of all Interleaved 2 of 5 barcodes to verify that the data complies with the check character algorithm. Barcodes passing the checks will be transmitted except the last one digits, whereas those failing them will not be transmitted. Transmit Check Characters After Verification: TThe scanner checks the integrity of all Interleaved 2 of 5 barcodes to verify that the data complies with the check character algorithm. Barcodes passing the checks will be transmitted, whereas those failing them will not be transmitted.