sdk-t6

sdk-t6 is an Expo module for T6 POS device integrations.

It currently provides:

• Magnetic card reader APIs
• Customer aid screen (top small screen) APIs
• Built-in thermal printer APIs
• Device info APIs (terminal serial number)

Platform support

• Android: supported
• iOS: not supported for hardware APIs (throws platform-not-supported errors)
• Web: not supported for hardware APIs (throws platform-not-supported errors)
• Expo Go: not supported (requires native module in a development build)

Installation

npm install sdk-t6

Important: vendor SDK binaries are not bundled

This package intentionally does not publish vendor .jar/.aar files to npm.

For Android hardware features to work, add the vendor JAR manually after install:

1. Obtain vendor SDK JAR from your device/vendor package.
2. Copy it to:
   • node_modules/sdk-t6/android/libs/T1_V2_20250826.jar
3. Rebuild your Android development client.

Android setup checklist

1. Use a development build (expo run:android), not Expo Go.
2. Ensure vendor JAR exists under node_modules/sdk-t6/android/libs/.
3. Rebuild after adding/replacing the JAR.
4. Run Metro with dev client:

npx expo start --dev-client -c

The module manifest includes required permissions:

• android.permission.CLOUDPOS_MAGCARD
• android.permission.CLOUDPOS_MAGCARD_GETTRACKDATA
• android.permission.CLOUDPOS_EMVL2
• android.permission.CLOUDPOS_PRINTER
• android.permission.CLOUDPOS_SYSTEMDEV

Quick usage

import SdkT6 from 'sdk-t6';
import type { MagCardEvent } from 'sdk-t6';
import { useEvent } from 'expo';

const event = useEvent(SdkT6, 'onMagCardEvent') as MagCardEvent | undefined;

await SdkT6.magOpenAsync();
const card = await SdkT6.readMagCardAsync(60_000);
await SdkT6.magCloseAsync();

Aid screen example:

await SdkT6.smallScreenWakeAsync();
await SdkT6.smallScreenSetBrightnessAsync(80);
await SdkT6.smallScreenDisplayTextAsync('USD 123.45', 'xlarge', 'center');

// Mixed sizes in one update (label + amount) — no flicker from sequential replace calls
await SdkT6.smallScreenDisplayRichTextAsync(
  [
    { text: 'Amount', textSize: 'normal', align: 'center' },
    { text: '\n\n' },
    { text: '1,250.00', textSize: 'xlarge', align: 'center' },
  ],
  'center',
  {
    fontFamily: 'sans-serif', // or 'fonts/Brand.ttf' in APK assets
    textColor: '#FFFFFF',
    backgroundColor: '#001122',
  }
);

Printer example:

await SdkT6.printTextAsync([
  { text: 'MY STORE', fontSize: 28, bold: true, align: 'center' },
  { text: 'TOTAL  $42.00', bold: true },
  { text: '\n\n' },
]);
await SdkT6.printCutPaperAsync('halt');

Device serial number:

const serialNo = await SdkT6.getSerialNoAsync();

API overview

Magnetic card:

• readMagCardAsync(timeoutMs?)
• cancelReadMagCardAsync()
• magOpenAsync()
• magCloseAsync()
• magSearchAsync(timeoutMs)
• magStopSearchAsync()
• event: onMagCardEvent

Aid screen:

• smallScreenWakeAsync()
• smallScreenSleepAsync()
• smallScreenSetBrightnessAsync(brightness)
• smallScreenGetBrightnessAsync()
• smallScreenGetSizeAsync()
• smallScreenDisplayTextAsync(text, textSize?, displayMode?)
• smallScreenDisplayRichTextAsync(items, displayMode?, options?) — mixed text sizes in one update
• smallScreenDisplayImageBase64Async(imageBase64, align?, options?)
• smallScreenStopAppControlAsync()

Rich text options (Android; whole-screen, not per item):

• fontFamily: system name (e.g. sans-serif) or asset path (e.g. fonts/Brand.ttf)
• textColor: CSS hex (#RGB / #RRGGBB / #AARRGGBB), default #FFFFFF
• backgroundColor: same hex formats, default #000000

Image options (Android):

• width, height (target image box size in pixels)
• padding, paddingHorizontal, paddingVertical, paddingLeft, paddingTop, paddingRight, paddingBottom
• contentFit: contain | cover | fill | none

Printer:

• printResetQueueAsync()
• printEnqueueTextAsync(items)
• printEnqueueImageBase64Async(imageBase64, align?)
• printEnqueueBarcodeAsync(content, width, height, align?)
• printEnqueueQrCodeAsync(content, size, align?)
• printFlushAsync()
• printTextAsync(items) (enqueue + flush)
• printEnhancedTextAsync(items)
• printOpenAsync()
• printCloseAsync()
• printGetStatusAsync()
• printGetMessageAsync()
• printSetGrayAsync(gray)
• printGetGrayAsync()
• printLineFeedAsync(lines)
• printCutPaperAsync(mode?)

Device info:

• getSerialNoAsync()

Module docs

• Magnetic card guide: docs/Magnet_card_module.md
• Aid screen guide: docs/Aid_screen_module.md
• Printer guide: docs/Printer_module.md
• Device info guide: docs/Device_info_module.md

Local example app

From this repository:

cd example
npx expo run:android
npx expo start --dev-client -c

Try these example screens:

• example/MagnetCardScreen.tsx
• example/AidScreen.tsx
• example/PrinterScreen.tsx
• example/DeviceInfoScreen.tsx

Troubleshooting

• ERR_MAG_SERVICE_UNAVAILABLE or ERR_SMALL_SCREEN_SERVICE_UNAVAILABLE or ERR_PRINTER_SERVICE_UNAVAILABLE or ERR_DEVICE_INFO_SERVICE_UNAVAILABLE:
  • vendor JAR missing, wrong path, or app not rebuilt
• ERR_MAG_BUSY:
  • another magnetic operation is already active
• Platform-not-supported error:
  • running on iOS/web or Expo Go

License

MIT