Abstract: An automated ordering system includes a central station and numerous subscriber stations, including customer and vendor stations, whose sales transactions are regulated by the central station. A communication link, such as the Internet, permits each station to transmit and receive requisitions, purchase orders, and invoices to an from the central station. Each remote stations uses its own internal item identification codes, preferably general ledger account codes, to identify products to be purchased or sold. The central station maintains a database identifying the codes used by each subscriber station and relating different codes used by other subscribing stations to identify similar products. A customer may transmit to the cental station a requisition for a product identified with the customer accounting code and specifying a particular vendor. Using its database, the central station composes a purchase order addressed to the specified vendor and identifying the required product with the vendor's code.