EDI Reference / segments / BAK
BAK

Beginning Segment for PO Acknowledgment

Opens an 855 and echoes the PO.

Key elements

ElementNameWhat it carries
BAK02 Acknowledgment Type AC = ack w/ detail/change, AK = ack no detail.
BAK03 Purchase Order Number Must match the 850's PO number.

Key elements only — the ones that matter in retail trade, not the full element list.

Appears in

855 · Purchase Order Acknowledgment

See a real BAK in context — paste any X12 and the Inspector breaks out every segment.

Inspect an X12 free