POS Condition Code
What it is
Condition under which the transaction takes place: attended, unattended, e-commerce, MOTO, recurring.
Example values
00Normal attended presentment.59E-commerce transaction — a Visa-defined value; codes beyond the ISO set are network/private.08Mail / telephone order (MOTO).DE 25 on the wire
Bitmap position
DE 25 is bit 25 of the primary bitmap: byte 4, mask 0x80. A primary bitmap with only DE 25 present reads 0000008000000000 in hex.
Length
DE 25 is fixed length: always 2 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 2 bytes when the message travels as text (ASCII or EBCDIC), or 1 bytes in binary dialects that pack digits as BCD.
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.