ISO 8583 · Data fields

Field 90Original Data Elements

pyiso8583 starter profilesIndependent explanation

What this field describes

This field is labelled Original Data Elements and uses a fixed forty two byte container in these profiles.

Use the implementation’s component positions to link back to an earlier transaction. The starter profile defines only the outer container.

Compare the two profiles

Container settings from the pinned pyiso8583 source.
Setting	`default`	`default_ascii`
Value encoding	ASCII	ASCII
Length limit	Exactly 42 bytes	Exactly 42 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 9042 bytesASCII value

Read exactly 42 value bytes. The next field begins immediately afterwards under this profile; no length prefix belongs to this field.

Find it in the bitmap

Bitmap: Secondary
Position: 26
Byte: 4
Bit in byte: 2

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.