Digital data exchange, or DDX, refers to the transfer of information between two or more digital devices. There are several synonyms for this term that are commonly used in the technology industry. One popular synonym is electronic data interchange, or EDI. This term refers specifically to the exchange of standardized documents, such as invoices and purchase orders, between businesses. Another synonym is electronic data transfer, or EDT. This term is generally used to refer to the transfer of large amounts of data, such as images or video, over the internet. Other synonyms include electronic data interchange messaging, electronic data exchange, and electronic data transfer methods.