Bar Code Filters

Some bar codes contain a checksum character. Usually the last character in the bar code, the checksum is used to determine the validity of the bar code. (The checksum is only used to determine if a bar code is valid; the checksum character itself is not part of the bar code data.) Not all bar code types support a checksum character. Of the bar code types that do, some support a mandatory checksum, while others support an optional checksum.

For bar code types that contain a mandatory checksum, such as Code 128 or EAN, the bar code driver always checks the checksum character to determine the validity of the bar codes. If the checksum fails, the bar code is not returned.

For bar codes that contain an optional checksum, such as Code 39 or Interleaved 2 of 5, the bar code driver only checks the checksum character if the Checksum check box is selected.

• If the Checksum check box is selected, the last character in the bar code is treated as a checksum character. If the checksum fails, the bar code is not returned. If the checksum succeeds, the bar code data is returned.
• If the Checksum check box is not selected, the last character of the bar code is treated as bar code data.

Optional checksum verification applies to the following bar code types:

• Codabar
• Code 39
• Interleaved 2 of 5

For all other bar code types, checksum verification is ignored; the Checksum setting is unavailable on the Bar Code Setup tab.

Select a predefined bar code format to filter out incorrect or irrelevant bar codes that are not related to your scan job. As a result, you ensure that only relevant bar codes are used with your index fields.

For example, suppose that you are scanning invoices that include bar code labels in Code 39 format. The invoices may contain many Code 39 bar codes, including some that you do not need to read because they are unrelated to your business purposes.

To continue the example, assume that the bar codes you need start with INV followed by an 8-digit number, such as INV12345678. You could avoid reading Code 39 bar codes with other values by specifying the required format as "INV"9(8). Then the desired bar code would be available for use in an index field, which would also have a validation mask defined with the format "INV"9(8). If the bar code is missed for some reason, the index validation will prevent the batch from being exported until the correct value is entered manually.

All the bar codes that pass the defined bar code filters are stored in sequence in the index default values named {BarCode1}, {BarCode2}, {BarCode3}, etc. (up to 128 possible bar code values are supported per page: 64 on the front and 64 on the back). Use these index default values to connect the correct bar codes to your index fields.

On the Index Setup tab, click the setup tool next to the Default field to access the bar code default values. Use the On Page setting to indicate the page on which the bar code appears.

Some 2D bar codes such as QR contain more than a thousand characters. A single 2D bar code can therefore contain values for multiple index fields. You can separate these values with a semicolon, tab, or line feed control character. Any data following the special characters is moved to the next bar code default value.

A single QR value contains the following information:

John Doe;Surgery;15MAR2008

Using the semicolon as a separator, the bar code reader automatically separates the content of the 2D bar code into three bar code default values.

• {BarCode1} = John Doe

• {BarCode2} = Surgery

• {BarCode3} = 15MAR2008

On the Index Setup tab, you could create index fields such as "Department" populated with index default value {BarCode2}, "Name" populated with index default value {BarCode1}, and "Admission Date" populated with index default value {BarCode3}.

You can associate any index field with any of the recognized bar codes. For example, the first index field "Department" is associated with the second bar code, and the second index field is associated with the first bar code.

You can also combine bar code default values into a single index field. To continue the preceding example, an index field called "Patient Identifier" using a default value {BarCode3} "-" {BarCode1} would result in "15MAR2008 - John Doe" as the Patient Identifier value.