The transaction set is the innermost envelope.

A transaction set is the EDI equivalent of a paperdocument such as a purchase order or invoice. In every EDI standardeach transaction set has a unique three-digit identifier called atransaction set ID.

A transactionset envelope surrounds a transaction set and is made up of transactionset header and trailer segments.

The following table describes the contents of the transaction setenvelope:

Contents

Description

Header

Transaction set ID specifying the transaction set type suchas a purchase order or invoice.

Trailer

Number of segments in a transaction set including the headerand trailer segments. The EDI translator will report any discrepanciesbetween this number and the actual number of segments processed.

Both header and trailer

Matching control numbers that uniquely identify the transactionset. Generally the sender EDI translator assigns the control numbers.Some translators monitor the control numbers for data sent and received.This monitoring verifies that the trailer is associated with the properheader and that no control numbers were skipped during the translation.If a control number is skipped a report is generated listing allskipped control numbers. A missing control number indicates that apiece of data was not sent or received.

Note: The TRADACOMS standarddoes not use matching transaction set control numbers.

The following figure shows the transaction set and its positionin the EDI envelope hierarchy: