This article has multiple issues. Unsourced material may be challenged and removed. ISO 8583 defines a message format iso 8583 specifications pdf a communication flow so that different systems can exchange these transaction requests and responses. ISO 8583 at some point in the communication chain, as do transactions made at ATMs.
ISO 8583 standard, as do many other institutions and networks. Although ISO 8583 defines a common standard, it is not typically used directly by systems or networks. These fields are used by each network to adapt the standard for its own use with custom fields and custom usages. Based on this information, the card issuing system will either authorize or decline the transaction and generate a response message which must be delivered back to the terminal within a predefined time period. 1987 and 1993 versions of the standard are no longer used in the 2003 version, which holds currency as a sub-element of any financial amount element. As of June 2017, however ISO 8583:2003 has yet to achieve wide acceptance.
Cardholder-originated transactions include purchase, withdrawal, deposit, refund, reversal, balance inquiry, payments and inter-account transfers. ISO 8583 also defines system-to-system messages for secure key exchanges, reconciliation of totals, and other administrative purposes. The Message Type Indicator is a 4 digit numeric field which indicates the overall function of the message. A Message Type Indicator includes the ISO 8583 version, the Message Class, the Message Function and the Message Origin, as described below. The first digit of the MTI indicates the ISO 8583 version in which the message is encoded.