Transaction Number - NSU

Indicates the sequence number (NSU – Unique Sequential Number) of the transaction assigned by the Host (System
of the Card Networks that receive and process requests for TEF transactions). When this field is sent
from the SiTef Client to the TEF requesting Terminal, it represents the Host NSU established for the
transaction and when it is sent from the TEF requesting Terminal to the SiTef Client, it represents the NSU of the
transaction to be handled (cancelled, confirmed, etc.). This field is numeric and has a size of up to 12 20
bytes.

In the TRNCENTRE sales transaction (ATTENTION: this field is informed in the response message of the
Sitef, and therefore should not be informed by the POS, which may, at its discretion, capture this information or
no)