A duplicate control number is a control number that Module for EDI believes has already been used and, therefore, might indicate a duplicate document. Generally, the module considers a control number to be a duplicate if the control number from the header is less than the next expected control number in the EDIControlNumber table (for example, the module receives an EDI document with control number 6, but the expected control number is 8).

However, a duplicate control number might be larger than the expected control number when the next expected control number is close to the minimum. Module for EDI uses the control number window to determine a range of numbers greater than the expected control number that should be considered duplicate, as shown in this example :

You define the action that you want Module for EDI to take if a document with a duplicate or out-of-sequence control number arrives. For example, you can set the module to prevent processing of documents with duplicate or out-of-sequence control numbers. For more information, see Actions Module for EDI Can Take for Invalid Control Numbers. Later, you can force the processing of these documents. For more information, see Reprocessing EDI Documents with Invalid Control Numbers and Reprocessing Documents with Out-of-Sequence Control Numbers.