Host transaction number (host nsu) of payment methods

Indicates the sequence number (NSU – Unique Sequential Number) of the transaction assigned by the Host (System of the Card Networks that receives and processes requests for TEF transactions) of n TEF transactions that have made to make a payment (equivalent to field 012-000, but to detail the form of selected payment). When this field is sent from the SiTef Client to the TEF requesting Terminal, it represents the NSU of the Host established for the transaction and when it is sent from the Terminal requesting TEF for the SiTef Client, it represents the NSU of the transaction to be handled (cancelled, confirmed, etc.). This one field is numeric and has a size of up to 12 20 bytes.