The document discusses how to use the available to promise (ATP) feature in Microsoft Dynamics AX2009 to determine when all quantities of an item can be delivered for a sales order. ATP shows the expected available quantity over time based on planned receipts and issues. The ATP time fence is determined by the item's site-specific order settings and controls how many days into the future the ATP slope is displayed. ATP considers only inventory availability, while capable to promise (CTP) also takes work center availability into account for produced items.