to reduce the probability of misreads occurring when the bar code is scanned at too large an angle so that the scanning beam crosses the top and/or bottom edge of the bar code rather than scanning across all bars, entering through the leftmost bar and exiting through the rightmost bar (or vice versa for a reverse scan). Such a "short scan" which does not extend through all of the bars obviously cannot result in a correct read of the complete bar code, but by the nature of the interleaved 2 of 5 code, it is possible for a short scan that begins in the middle of the bar code to begin with a pattern that corresponds to the required start pattern, or for a short scan that ends in the middle of the bar code to end with a pattern that corresponds to the required stop pattern. In this way the short scan, though incorrect, may appear to be a correct full scan. The Bearer Bar prevents this error, as a short scan will pass through the Bearer Bar as it passes across the top or bottom edge of the bar code. Since the Bearer Bar is much wider than any legitimate black bar, it will ensure that the short scan cannot appear to begin with the correct start pattern and end with the correct end pattern, forcing an invalid scan. The bar code can then be re-scanned, either automatically or manually. (If the short scan was not recognized as invalid, the misread data would be accepted and used as if it was good data, and there would be no chance to automatically rescan the bar code to correct the bad data.) On 135 film (35 mm) canisters, interleaved 2 of 5 is used to identify the manufacturer, the film type, number of exposures and proprietary information in 6 digits. The barcode is located between the electrically read silver and black DX Camera Auto-Sensing Code and the film can exit lip. It is optically scanned by many film-processing machines when the cartridge is inserted for developing. Identcode and Leitcode are variants of interleaved 2 of 5 with check digits used by Deutsche Post. See also ITF-14 Two-out-of-five code Linear barcodes References Barcodes