> ## Documentation Index > Fetch the complete documentation index at: https://docs.stackra.figentra.com/llms.txt > Use this file to discover all available pages before exploring further. # 0459 — PAX terminals: the built-in printer, drawer and scanner through the NeptuneLite SDK > Proposed · 2026-10-27 > [!NOTE] > > Proposed (batch stackra-50, STA-1097, STA-904). The vendor-SDK ADR that 0442 decision 4 and 0253 > decision 3 ask for, for the `pax` family. Certification pending: written from PAX's public SDK > documents, not yet checked on a certified model. > [!NOTE] > > Amended by > [0478](https://docs.stackra.figentra.com/adr/0478-native-code-lives-only-in-expo-module-packages-one-per-capability-behind-a-port.md) > (2026-10-28): decision 2's Kotlin moves out of the till app's `src/native-sources/pax/` into the > printer, drawer and scanner module packages, split by capability, and the drivers move with it. > The rest of this page stands. ## Context 0442 (accepted by the owner on 2026-10-27, decision D4 of the Stackra finish plan; its page still waits to land here) gives the commerce till an Android target and asks for one ADR per vendor SDK before a family's first build (0442 decision 4, [0253](https://docs.stackra.figentra.com/adr/0253-peripherals-web-api-first-and-device-presets.md) decision 3). PAX's terminals have a built-in printer, a drawer port and a built-in scanner that no Web API or LAN path reaches; only PAX's SDK does ([0339](https://docs.stackra.figentra.com/adr/0339-point-of-sale-peripherals-printers-labels-drawer-scanner-display-and-the-native-bluetooth-driver.md) open detail 2). ## Decision 1. **Driver name `pax`.** `@stackra/peripherals` ships `PaxReceiptPrinterDriver`, `PaxCashDrawerDriver` and `PaxBarcodeScannerDriver` in its `./native` entry, behind the unchanged `ReceiptPrinter`, `CashDrawer` and `BarcodeScanner` ports, selected by `peripherals.printer`, `.drawer` and `.scanner` set to `pax`. 2. **One Expo module, `StackraPax`, a pass-through.** The till app links an Expo module named `StackraPax` only when its runway lists `device:pax` (0442 decision 3). It exposes `printerStatus()`, `printLines(lines)`, `openDrawer()` and an `onScan` event carrying `{ code }`, each a direct call to PAX's NeptuneLite API (`IDAL`): its printer (`init`, text printing, `start`, `getStatus`), its cash drawer on models with a drawer port, and its scanner with a result listener. The module maps nothing: it returns the SDK's own status number and the decoded text. Its Kotlin lives in the till app's `src/native-sources/pax/` ([0345](https://docs.stackra.figentra.com/adr/0345-native-code-generation-and-the-native-shared-layer.md) decision 6). 3. **Readiness in the driver.** `IPrinter.getStatus()` answers 0 when the printer is ready; every other value (busy, out of paper, overheated, voltage too low, a malfunction) refuses, with capability `print` (ADR 0250 decision 3). The drawer is driven by the printer, so it checks the same status before each kick; the kick is one-way. 4. **Text, not commands.** Receipt lines go to the SDK as text with control characters removed; the SDK draws them. Arabic shaping is the SDK font's and is a certification row. A raster or code-page path is not built. 5. **Absent means refused.** In a build without `StackraPax` (web, desktop, another family) the printer and drawer refuse with `print` and the scanner with `scanner`; a subscription there does nothing. No call throws at the till. 6. **The SDK stays the vendor's.** The SDK artefacts come from the PAX developer portal (PAXSTORE developer centre) under PAX's terms and are linked by the till app's build only; this repository holds no PAX binary or source. ## Consequences * The till drives a PAX terminal's printer, drawer and scanner with the same ports and settings as the desktop till. * The status table is one line of `POS_DEVICE_FAMILIES`; the tests replay transcribed SDK answers until certified models are recorded (STA-739), and a wrong code shows there first. * The Kotlin module, the config plugin that removes it from other families' builds, and the model list are the till template's and Runway's work (0442 decisions 3 and 5), not this package's. * Card payment, the label printer and the scale on these terminals are not covered; an acquirer SDK is its own ADR (0442 decision 6). The second screen stays the `external` customer display (0430). ## Enforcement * `packages/experience/peripherals/src/native/**/__tests__/*.test.ts` replay the `pax` fixture through a stand-in `StackraPax` module. * planned — a certification run on each certified PAX model (STA-739) records the fixture again; Runway refuses an Android till build listing `device:pax` without this ADR (0442 enforcement). ## Supersedes and sources `Supersedes: none`. Sources: owner decision D4 of 2026-10-27 (`notes/handover/batches/STACKRA-FINISH.md`), the 0442 draft (`notes/handover/app-shells/adr/0442-native-android-till-for-pos-terminals-from-the-commerce-till-template.mdx`), PAX's public SDK documents, STA-904, STA-1097. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.