If you obtained a webpage about their intended data source, and specifics about their destination information bank = confusion could be focused.
Assuming the "EDI" acronym is the most basic one - http://en.wikipedia.org/wiki/Electronic_data_interchange
Electronic data interchange (EDI) is an electronic communication system that provides standards for exchanging data via any electronic means. By adhering to the same standard, two different companies, even in two different countries, can electronically exchange documents (such as purchase orders, invoices, shipping notices, and many others). EDI has existed for more than 30 years, and there are many EDI standards (including X12, EDIFACT, ODETTE, etc.), some of which address the needs of specific industries or regions. It also refers specifically to a family of standards.
Difference Between EDI and IDOC
Explain to me about Idoc?
IDoc (for intermediate document) is a standard data structure for electronic data interchange (EDI) between application programs written for the popular SAP business system or between an SAP application and an external program. IDocs serve as the vehicle for data transfer in SAP's Application Link Enabling (ALE) system.
A Google for "EDI and filemaker" gives your question Link #9 (not a good sign of information being easily available)
Similarly a Google for "iDoc site:forums.filemaker.com" returns very few links, mostly about a user on these forums named "iDoc"
Thank you for the responses. Are there specific questions you would suggest I ask to find out the right information about the external server and the internal server? I feel like once I know what the file formats need to be I could dig deeper and understand how to get that information to flow through Filemaker Pro. You hit on one thing in your first post about invoices. They want me to find a way to access the external server to obtain information about a request for products, then that information moves through to the internal server to produce an invoice and take that information back to the external server and so on.