F 47-ADDITIONAL DATA (NATIONAL): This is a field reserved for additional information needed for domestic purposes.
In Turkey, this is the field used in authorization transactions to carry the BKM Unique ID and information specific to KKPT (card-to-card money transfer) transactions.
The details of the F47 field are as follows:
| Position | Value |
| 1-8 | BKM Unique Merchant Id |
| 9-255 | KKPT Special Data |
F47's place in the message
In the ISO 8583 standard, certain fields are reserved for use specific to particular countries and networks. F47 is the "additional data - national" field. Similarly, F46 is reserved for international use, and F48 is reserved for additional data for private use. The content of these fields is not defined by the standard; it is determined by the specification of the network that uses the field.
It is a variable-length field
F47 is a variable-length field. Before the field data, a length indicator showing how many characters the content contains is sent. The system parsing the message first reads this length, then takes that many characters as the content of F47. Miscalculating the length is a common integration error, since it can cause every subsequent field in the message to be read incorrectly.
Usage in Turkey
In domestic card transactions, F47 is populated according to the format defined by BKM. The BKM Unique Merchant Id ensures that the merchant where the transaction took place is uniquely identified across the BKM system. For card-to-card money transfer transactions, information specific to that transaction follows in the rest of the field.
For this reason, the content of F47 may differ for transactions coming from abroad or transactions carried out over a different network. Teams performing integrations need to base the meaning of each position in the field on the current message specification of the relevant network.
