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SchemeLens

ISO 8583:1987 response code

A0

Reserved for national use

Standard version
ISO 8583:1987
Paired version code
No direct pair assigned

In ISO 8583:1987, response code A0 means “Reserved for national use”. The reviewed dataset contains an entry for UnionPay; 4 of the five scheme columns remain N/A.

Merchant handling

Actions to be taken

Do not infer a merchant action from this reserved value. Use the exact acquirer or processor specification that assigned the code before continuing the transaction.

This is conservative merchant guidance derived from the published response meaning. Current scheme, acquirer, processor, merchant advice, and transaction-specific rules take precedence.

Scheme comparison

Descriptions in the reviewed sources

Each populated value links to its scheme record and preserves the raw code published by that source. N/A means no matching description exists in the reviewed public dataset.

Scheme descriptions compared with ISO 8583:1987 response code A0
SchemeRaw codeSource descriptionEvidence
VisaN/AN/AN/A
MastercardN/AN/AN/A
American ExpressN/AN/AN/A
DiscoverN/AN/AN/A
UnionPayA0Message authentication code verification failedOfficial, limited scope

Standard sources

Version and response-name evidence