Lexmark X864 Forms and Bar Code Technical Reference - Page 158

Symbology MSI +CHK10 MSI +CHK10 +CHK10 MSI +CHK11 +CHK10 Typeface 24761T 24762T 24763T Max characters 453 452 452 The maximum amount of encodable data possible within a bar code is an interesting metric, but it not does matter practically. Because there is no specification that calls out the absolute limit for any 1D bar code, good judgment must be used on the effort devoted to testing this metric. Note: If bar code image corruption occurs when excessive amounts of data are encoded, then the amount of encoded data should be reduced, or the user should change to a more capable bar code symbology. Four-state Postal Widths The BCE creates 4-state postal images that may not be exactly the same as HP BDP or the LXK BCC. The number of bars and spaces are the same, the proper ascenders and descenders are used, and the bar code scans correctly with a verifier. A change in the BCE to address this minor difference may be implemented in a later version. Note: Exact size compatibility of certain 4-state bar code image sizes with previous Lexmark bar code options is not assured. However, the proper order and placement of the bars and spaces is the same, and the bar code will also scan correctly. If the bar code image is too wide and will not fit within the available space, users should either resize their form to allow placement of current and previous bar code images, or slightly reduce the size of the image using the available PCL or Postscript controls. If the datastream controls are adjusted for a smaller width, the corresponding image should be smaller on both current and previous bar code products, and the image should fit within the available space. HRT Widths and Heights The BCE uses the FreeType font renderer with custom SuchyMIPS-generated fonts to produce the HRT (human readable text) on bar codes. In certain cases, the HRT may be larger or smaller, or may not be positioned horizontally or vertically exactly as on the HP BDP or the LXK BCC. However, the HRT should be readable, legible, and approximately the same as the target platforms. PDF417 Image Widths and Heights The BCE generates PDF417 images, based on the algorithms found in the AIM PDF417 specification. The implementation of a PDF417 can differ between manufacturers, depending on the interpretation of the specification. Because of this, certain combinations of character lengths and ECC levels can produce images that differ slightly in the number of rows and columns from HP BDP or LXK BCC. Deviations 155