• Belgian Customs (sender)
• Shipping company or ship's agent (receiver, in response to CUSREP)
• Shipping company or cargo agent (receiver, in response to CUSCAR). There is only one ship's agent per ship, but there may be several cargo agents in the case of co-shipment
• In the case of CUSCAR-CIM: the rail operator (receiver, in response to CUSCAR)

• The unique reference of the EDIFACT message

- In order to relate the CUSRES response message to the EDIFACT message previously sent,

- In the case of a CUSREP and/or CUSCAR message: the document number notified by the ship's agent or cargo agent in the BGM segment - composite data element 1004.

• The response message (the processing indicator) which indicates whether the message has been accepted or not by the PLDA system.

- If it has been rejected, the CUSRES message also indicates the location of the error in the original message together with one or more error codes for the reason why the original EDIFACT message has not been accepted, or not fully accepted.

Depending on the situation and the type of message, an EDIFACT may nevertheless be partially accepted by Customs (see Message Implementation Guides).