Authorization ID Response Length
What it is
Maximum length of the authorization response the acquirer can handle.
DE 27 on the wire
Bitmap position
DE 27 is bit 27 of the primary bitmap: byte 4, mask 0x20. A primary bitmap with only DE 27 present reads 0000002000000000 in hex.
Length
DE 27 is fixed length: always 1 digits, with no length prefix. A parser reads exactly that many and moves on, so shorter values are right-aligned and padded with leading zeros.
Size in the message
At most 1 bytes when the message travels as text (ASCII or EBCDIC).
Format n
Format n means numeric: the digits 0–9 only.
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.