ISO 8583 DE Reference
Format: ansLength: ...999Variable (LLLVAR — 3-digit length prefix)
DE 57

Reserved — National

Data element
57
Format
ans
Length
...999
Encoding type
LLLVAR
Bitmap
Primary

What it is

Reserved for national use. Some networks: authorization life-cycle data.

Specification reference

Defined in ISO 8583:1987 (base). Card networks publish their own dialect tables (Visa BASE I / V.I.P., Mastercard CIS) that refine formats, lengths, and — for private-use elements — the entire layout. Always confirm against the interface specification you implement.

Decode & build this element

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