The KIX barcode (Klant index)
- Used for mail sorting by the postal service of the Netherlands, Koninklijke TNT Post (Royal TNT Post)
- Regarded as “four-state” because there are four types of bars, classified by presence of ascenders and/or descenders
- Transcribable using DAFT notation
- Used by a number of countries in their postal systems, though the specific symbologies by which they encode characters can vary
- Encodes alphanumeric characters, and is a slight variant of the Royal Mail 4-State system, omitting the start and end symbols and checksum