ISO 8583 · Data fields

Field 41Card Acceptor Terminal ID

pyiso8583 starter profilesIndependent explanation

What this field describes

This fixed eight byte field identifies the card acceptor terminal in the selected profiles.

Apply the connection’s padding and identifier rules. A terminal identifier is separate from a merchant or card acceptor identifier.

Compare the two profiles

Container settings from the pinned pyiso8583 source.
Settingdefaultdefault_ascii
Value encodingASCIIASCII
Length limitExactly 8 bytesExactly 8 bytes
PrefixNoneNone

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 418 bytesASCII value

Read exactly 8 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
41
Byte
6
Bit in byte
1

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.