The 850 Purchase Order is the most widely used EDI transaction set. It allows buyers to electronically request goods or services from a supplier, replacing paper or fax-based PO processes.
BEG
Beginning Segment — PO number, type, and date
PO1
Baseline Item Data — line item, quantity, unit price
DTM
Date/Time Reference — ship-by date, delivery window
N1
Name — identifies Ship-To, Bill-To, and Buying Party
CTT
Transaction Totals — number of line items
850 PO sent by buyer → Supplier responds with 855 PO Acknowledgment → Supplier ships and sends 856 ASN → Supplier invoices with 810.
Common 850 errors: missing BEG02 (PO number), mismatched unit of measure in PO1, and wrong date format in DTM (use CCYYMMDD).