When a customer submits an 850 Purchase Order, often they will reference their own internal stock code on the order rather than AEC's stock code. We can go ahead and enter the order after we cross reference the customer's stock code with the correct AEC stock code. Basically the cross reference tells the system that when this customer orders this part number use AEC's part number "xxxxxx".
When SYSPRO searches for a match against the stock code on the customer's EDI PO, it searches AEC's Stock Code Table. If it doesn't find a match, it then searches the Customer Stock Code Cross Reference (or Interchange) Table. If a customer orders a stock code that DOES EXIST in the AEC Stock Code table but it's the wrong STOCK CODE NUMBER for what they are ordering, the system won't recognize an entry if you try to cross reference it in the Customer Cross Reference table. The reason for this is that when the system hits a match in the AEC Table, it stops processing. It will never go on and search the Cross Reference Table. The proper thing to do in this case would be to let the system import the Purchase Order with the incorrect stock code and then change the stock code after the order is imported. Once you correct the stock code on the line, you can use the reference on that line of "IS" for Item Substitution Made. This will flag their system that the stock code has been changed.
For more information on how to enter a Customer Stock Code Cross Reference, search the How To for Customer Stock Code Cross Reference.