Format: ansLength: ..28Variable (LLVAR — 2-digit length prefix)
DE 102
Account Identification 1
What it is
The "from" account in transfers and inquiries — account number or IBAN, per network convention.
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.