ISO 8583 is the standard for real-time messages in the payments industry, essential for transactions between acquirers, card networks, and issuers. Originally defined in 1987, the standard specifies message structures, field names, and lengths, like the primary account number in field 2. It allows for flexibility in serializing fields, such as using EBCDIC for mainframes or packed BCD for numeric data. Different networks have unique specifications, with Visa’s VisaNet having numerous clients on various platforms. The standard evolved to accommodate new fields and nested sub-fields, with formats like tables, nested bitmaps, and Tag-Length Value messages. Implementing parsers for ISO 8583 messages can be complex, requiring attention to network-specific differences.
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