ISO 8583 DE Reference
Format: anLength: 1Fixed length
DE 91

File Update Code

Data element
91
Format
an
Length
1
Encoding type
fixed
Bitmap
Secondary

What it is

Action for file-update messages (0300): add, change, delete, inquiry.

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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