# Code One > Source: https://docs.barcoder.ai/docs/standards/code-one > research date 2026-06-03 · extracted at 2026-10-03 > Publisher: Barcoder — encyclopedia of QR, barcode and payment-code standards Specifications: - [Code One — BarTender Barcode Guide (Seagull Scientific)](https://barcodeguide.seagullscientific.com/Content/Symbologies/Code_One.htm) - [Code 1 — Rosistem Barcode Education](https://www.barcode.ro/tutorials/barcodes/code1.html) ## Overview Code One (also written Code 1) is a two-dimensional matrix barcode symbology built from dark and light square data modules together with fixed recognition and reference patterns. Its defining structural feature is a horizontal-and-vertical finder pattern of bars crossing the **middle** of the symbol (rather than the corner finders of QR Code or the L-shaped finder of Data Matrix), with the data arranged in rows on either side [1][1] [2][2]. Because it stores data in two dimensions it must be read with imaging (CCD/camera) scanners rather than a moving laser line [2][2]. ## History Code One was invented by **Ted Williams of Laserlight Systems, Inc.** Sources date the invention to **1991 or 1992** [1][1] [2][2] — Seagull's guide says 1991, while Rosistem and several secondary references say 1992. It is consistently described as the **first two-dimensional matrix symbology released into the public domain** [1][1] [2][2]. Ted Williams was a prolific symbology designer who also created Code 128 and the stacked Code 16K [7][7]; Code One belongs to the same early-1990s wave of high-density 2D matrix codes that includes Data Matrix. ## Technical specification A Code One symbol consists of square data modules plus fixed patterns used for recognition and reference, organised as rows of data flanking a central cross-shaped finder pattern [1][1] [2][2]. There are **ten versions**: eight standard sizes labelled **A through H**, plus two special variants **S** and **T** [1][1] [2][2]. - **Versions A–H** are the general-purpose sizes and require no quiet zone [1][1]. Capacity scales steeply across them: the smallest, Code 1A, holds about **13 alphanumeric characters or 22 digits**, while the largest, Code 1H, holds about **2,218 alphanumeric characters or 3,550 digits** (one source gives 1,480 Full-ASCII characters at version H) [1][1] [2][2]. The maximum symbol measures roughly 134X wide by 148X high [2][2]. - **Versions S and T** use different structures intended for direct inkjet printing: version S was designed for an eight-nozzle inkjet printer and version T for a 16-nozzle inkjet printer; both require a minimum 1X quiet zone on all sides [1][1]. Code One supports **all 256 ASCII characters**, a pad/message-separator character, 8-bit binary data, function characters, and industry-standard escape sequences for international code pages [1][1] [2][2]. Error correction uses the **Reed-Solomon** algorithm; the amount of error-correction data is fixed per version and is not user-definable [1][1] [2][2]. The symbology can also be laid out in non-rectangular configurations such as L, U and T shapes [2][2]. ## Use cases Code One has seen limited but real deployment. Reported applications include **healthcare/pharmaceutical labelling** and **waste-management container sorting** [2][2]. It has historically been associated with certain **Intermec printers** that supported it as an output format [1][1]. Overall adoption has been modest relative to Data Matrix, which captured most of the small-item 2D marking market. ## Implementations - **Zint** (`github.com/zint/zint`) — open-source C encoding library; its symbology appendix and manual confirm Code One support [3][3] [4][4]. - **BarTender / Seagull Scientific** — commercial label software documents Code One as a supported symbology, including versions A–H, S and T [1][1]. ## Comparison - **vs. Data Matrix** — Code One and Data Matrix are contemporaries (early 1990s) and both are square-module, Reed-Solomon-protected 2D matrix codes, but they differ structurally: Data Matrix uses an L-shaped solid finder ("L" plus a dashed clock track) on two edges, whereas Code One uses a **central cross finder** with data in rows on either side. Code One was notable as the *first* public-domain 2D matrix code; Data Matrix went on to become the dominant small-item marking symbology and the one standardised as ISO/IEC 16022, leaving Code One a comparative footnote [1][1] [2][2]. - **vs. QR Code** — both are 2D matrix codes requiring imaging scanners, but QR's three corner position-detection patterns and timing patterns differ entirely from Code One's central finder; QR achieved mass consumer adoption that Code One never approached [2][2]. ## Fun facts - Code One was the **first matrix symbology placed in the public domain**, a deliberate openness choice years before QR Code was likewise made freely usable [1][1] [2][2]. - Its inventor Ted Williams also designed **Code 128** and **Code 16K**; the "128" name reflects the symbology encoding all 128 ASCII values, and 128² = 16,384 ≈ "16K", the basis of Code 16K's name [7][7]. - The special **S and T versions** were engineered around specific inkjet print heads (8- and 16-nozzle), an unusually hardware-specific design choice for a barcode symbology [1][1]. ## Status Niche / legacy. Code One is a fully specified, public-domain symbology with continuing software support (Zint, BarTender) [1][1] [3][3], and it retains small footholds in healthcare and industrial sorting [2][2]. In practice it was eclipsed by Data Matrix for nearly all the use cases it was designed for, and it is rarely encountered today. Confidence is medium: technical details are well-documented across multiple sources, but the invention year is reported inconsistently (1991 vs 1992) and current deployment figures are not quantified in available sources. ## Sources [1] [Code One — BarTender Barcode Guide](https://barcodeguide.seagullscientific.com/Content/Symbologies/Code_One.htm) — Seagull Scientific. [2] [Code 1 — Barcode Education](https://www.barcode.ro/tutorials/barcodes/code1.html) — Rosistem. [3] [zint/zint barcode encoding library](https://github.com/zint/zint) — GitHub. [4] [Zint Manual — symbology appendix](https://zint.org.uk/manual/appendix/B) — Zint project. [5] [Data Matrix](https://en.wikipedia.org/wiki/Data_Matrix) — Wikipedia. [7] [Code 16K](https://en.wikipedia.org/wiki/Code_16K) — Wikipedia (Ted Williams / Code 128 / Code 16K background). [1]: https://barcodeguide.seagullscientific.com/Content/Symbologies/Code_One.htm [2]: https://www.barcode.ro/tutorials/barcodes/code1.html [3]: https://github.com/zint/zint [4]: https://zint.org.uk/manual/appendix/B [5]: https://en.wikipedia.org/wiki/Data_Matrix [7]: https://en.wikipedia.org/wiki/Code_16K ## Deployments _No country reports mention this standard by name._ ## Regions / aggregations not mapped to a single country - Universal