Internal (multicompany) EDI
In external EDI, ASCII files must be transferred over commercial or noncommercial networks. This transfer requires you to translate the ASCII files to and from standardized encrypted messages. The encryption of the message ensures high data integrity and security and provides a universal format supported by all parties.
However, in multicompany EDI implementations (also referred to as internal EDI), the ASCII files are transferred over the internal company network (LAN or WAN), which means that you do not need to encrypt the files. In addition, because all companies in the multicompany structure use the same format for the ASCII files, you need not translate to an external EDI standard, such as EDIFACT or ANSI X12.
You can only perform internal EDI between companies that share a common directory on the company network (either through the use of the same data server or through NFS). In addition, all companies must use the same application server to, for example, allow company A to start a background process in company B that reads messages just sent from A to B. If this real-time transfer of messages is not required, the transfer of internal EDI messages is similar to an external EDI situation, except for the translation and communication software.