ISO 8583 · Data fields

Field 27Authorizing ID Response Length

pyiso8583 starter profilesIndependent explanation

What this field describes

The profile label identifies the length of an authorizing ID response. The field itself has a one byte container.

Keep the described response length distinct from the length of this field on the wire.

Compare the two profiles

Container settings from the pinned pyiso8583 source.
Setting	`default`	`default_ascii`
Value encoding	ASCII	ASCII
Length limit	Exactly 1 bytes	Exactly 1 bytes
Prefix	None	None

Length limits describe encoded values. They exclude any length prefix. The profiles can be customized; these settings do not establish the required fields or accepted values for a live connection.

Read the field boundary

Field 271 bytesASCII value

Read exactly 1 value bytes. The next field begins immediately afterwards under this profile; no length prefix belongs to this field.

Find it in the bitmap

Bitmap: Primary
Position: 27
Byte: 4
Bit in byte: 3

Positions start at one. Bits are counted from the most significant bit of each bitmap byte. This calculation locates the field’s presence indicator, not its value.