MaxiCode
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MaxiCode is a public domain, machine-readable symbol system developed by United Parcel Service (UPS) in 1992.cite-ref-1[1] Designed for tracking and managing package shipments, it resembles an Aztec Code or QR code but uses dots in a hexagonal grid instead of square grid. It is standardized under ISO/IEC 16023.cite-ref-2[2]cite-ref-3[3]
A MaxiCode symbol—also called "Bird's Eye", "Target", "dense code", or "UPS code"—is a 1-inch square with a central bullseye surrounded by hexagonal dots. It stores about 93 characters, and up to 8 symbols can be linked to carry more data. The symmetrical bullseye aids in fast, accurate scanning, even on moving packages.
Contents
• Modes
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Structured Carrier Message
MaxiCode symbols using modes 2 and 3 include a Structured Carrier Message containing key information about a package. This information is protected with a strong Reed–Solomon error correction code, allowing it to be read even if a portion of the symbol is damaged. These fields include:
1. A 4-bit indication of the mode in use, currently either mode 2 or mode 3.
2. A national or international postal code. MaxiCode supports both numeric postal codes (e.g. a ZIP Code), and alphanumeric postal codes.
3. A 3-digit country code encoded per ISO 3166
4. A 3-digit class of service code assigned by the carrier
The structured portion of the message is stored in the inner area of the symbol, near the bull's-eye pattern. (In modes that do not include a structured portion, the inner area simply stores the beginning of the message.)
Application-specific information
Irrespective of mode, a variable amount of application-specific information can be encoded in a MaxiCode symbol. This format of this additional data is not strictly defined, and amongst other information may include:
• Purchase order number
• Invoice number
• Indicator of the originating carrier
Modes
• Mode 0 – Obsolete; replaced by Modes 2 and 3. Older printers with outdated firmware may still produce it. Identifiable by two white horizontal hexagons in the upper right corner (black in all other modes).cite-ref-4[4]
• Mode 1 – Obsolete; replaced by Mode 4.
• Mode 2 – Structured Carrier Message with numeric postal code (mainly for U.S. domestic use).
• Mode 3 – Structured Carrier Message with alphanumeric postal code (mainly for international use).
• Mode 4 – Unformatted data with Standard Error Correction.
• Mode 5 – Unformatted data with Enhanced Error Correction.
• Mode 6 – Used for programming hardware devices.
UPS labels use Mode 2 or 3 MaxiCodes.
References
cite-note-11. ↑ citerefdr-randal-c-nelsonDr. Randal C. Nelson. "Bar Codes". University of Rochester. Retrieved 2023-02-20.
cite-note-22. ↑ "ISO/IEC 16023:2000". International Standards Organization. Retrieved 20 December 2018.
cite-note-33. ↑ "Technical Specifications – MaxiCode". Qrme. Archived from the original on 2025-06-04. Retrieved 2025-06-04.
cite-note-44. ↑ "MaxiCode Special-Function Parameters". IBM. Retrieved 2025-06-04.
External links
• Source for official MaxiCode technical specification
• Information about MaxiCode is available in US Patents U.S. patent 4,874,936, U.S. patent 4,896,029, and U.S. patent 4,998,010