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Scale

Cashier Manager

Brother POS integrates with USB scales through the Web Serial API, allowing you to weigh products directly at the register and capture the weight into the cart. The system supports automatic baud rate detection, live weight readings, and a manual weight entry fallback for situations where the scale is unavailable.

Weight Selection

Before You Begin​

  • Your scale must connect via a USB-to-serial adapter (RS-232 to USB). Common chipsets include Prolific (PL2303), FTDI (FT232R), Silicon Labs (CP210x), and QinHeng (CH340/CH341).
  • The Web Serial API must be supported by your browser. This is available in Google Chrome and Microsoft Edge on desktop. Safari and Firefox do not support Web Serial.
  • The scale integration setting must be enabled in your store settings.
  • Your browser may need permission to access the serial port the first time you connect.
Browser compatibility

The Web Serial API is only available in Chrome and Edge on desktop operating systems. It is not supported on iOS, Android, Firefox, or Safari. If your register uses an unsupported browser, use the manual weight entry fallback.

Connecting a Scale​

First-Time Setup​

  1. Plug the scale into a USB port on your register computer using a USB-to-serial adapter.

  2. Open the POS register in your browser.

  3. Open Scale Settings by tapping Printer Settings in the header bar and navigating to the scale configuration.

  4. Tap Connect Scale. The browser shows a port selection dialog listing available serial ports.

  5. Select the port that corresponds to your scale. USB-to-serial adapters are typically labeled with the chipset name.

  6. Choose a connection method:

    MethodDescription
    Auto-detect baud rateBrother POS tries common rates (9600, 4800, 2400, 1200) and picks the one that produces valid readings
    Manual baud rateYou specify the baud rate if you know it (9600 is the most common)

  7. Once connected, a scale indicator appears on the POS screen showing the live weight reading.

Auto-Detect Baud Rate​

The auto-detect feature tries each baud rate in sequence and listens for valid scale frames:

  1. Tap Auto-Detect in the scale settings.
  2. The browser shows the port selection dialog (requires a user gesture for security).
  3. Select your scale's port.
  4. A progress indicator shows which baud rate is being tested.
  5. When a valid frame is detected, the connection is established at that rate.
  6. If no valid frame is found at any rate, the detection reports failure.
9600 baud is the most common

Most retail scales operate at 9600 baud. If auto-detect is taking too long, try connecting manually at 9600 first.

Auto-Reconnect​

After the first successful connection, Brother POS remembers the authorized port. On subsequent visits:

  • The system automatically attempts to reconnect to the previously authorized port.
  • No user gesture is required for auto-reconnect.
  • If the scale is not plugged in, the auto-reconnect silently fails and the manual fallback is available.

Reading Weight​

Live Weight Display​

When connected, the scale sends continuous weight readings to the POS. The scale indicator shows:

IndicatorMeaning
Weight valueThe current reading (e.g., "3.5g")
UnitThe measurement unit (g, kg, oz, lb)
Stable indicatorWhether the reading is stable or the item is still settling
Overload warningAppears when the item exceeds the scale's capacity

Stability​

The scale reports whether the current reading is stable (item has settled) or in motion (still settling):

  • Stable -- the weight is reliable and can be used.
  • In motion -- wait for the item to settle before capturing the weight.

Brother POS visually distinguishes between stable and unstable readings so you know when the weight is ready to use.

Using the Scale During a Sale​

Weighing a Product​

  1. Place the product on the scale. Wait for the reading to stabilize.
  2. Add the weight-based product to the cart (search or scan).
  3. The weight selection modal opens. If the scale is connected, the live weight reading appears in the modal.
  4. Tap "Use Scale Weight" to capture the current stable reading, or select a preset weight if preferred.
  5. The product is added to the cart at the captured weight with the corresponding price calculated.

Manual Weight Entry​

If the scale is not connected or not functioning:

  1. Add the weight-based product to the cart.
  2. In the weight selection modal, type the weight manually using the number pad.
  3. Confirm the weight to add the product to the cart.
info

Manual weight entry is always available as a fallback, even when a scale is connected. This ensures you can continue serving customers if the scale has issues.

Supported Units​

UnitFull NameCommon Use
gGramsCannabis and small quantities
kgKilogramsBulk items
ozOuncesCannabis (1 oz = 28g)
lbPoundsLarger bulk items

The scale determines which unit to report. You can change the unit on the scale hardware itself (typically via a button on the scale). Brother POS reads whatever unit the scale sends.

Connection Issues​

If you are having trouble connecting your scale, check the Troubleshooting table below. If the issue persists, contact Brother POS support for assistance.

Troubleshooting​

ProblemSolution
"Connect Scale" button missingThe scale integration setting is not enabled. Ask your admin to enable it.
Browser does not show port dialogYou are using an unsupported browser. Switch to Chrome or Edge on desktop.
Port dialog shows no devicesThe USB-to-serial adapter is not recognized. Try a different USB port or adapter. Check that the OS has the appropriate driver (most are plug-and-play on modern systems).
Connected but no readingsWrong baud rate. Try auto-detect or test each rate manually.
Readings are garbledWrong baud rate or encoding. Use debug mode to inspect the raw data.
"Overload" warningThe item exceeds the scale's weight capacity. Use a higher-capacity scale.
Weight reading fluctuatesThe item has not settled. Wait for the stable indicator before capturing. Ensure the scale is on a level, vibration-free surface.
Scale disconnects randomlyCheck the USB cable connection. A loose adapter can cause intermittent disconnections.

Best Practices​

  1. Tare the scale before each weighing. Press the tare button on the scale to zero it out, especially if using a container.
  2. Wait for stability. Always capture the weight when the stable indicator is showing. Motion readings are unreliable.
  3. Keep the scale clean. Product residue on the weighing platform affects accuracy.
  4. Use auto-detect on first setup. It saves time guessing the baud rate.
  5. Have manual entry as a backup plan. Train staff on manual weight entry so they are not blocked if the scale has issues.
  6. Place the scale on a stable surface. Vibrations from foot traffic or other equipment can cause inaccurate readings.

What's Next?​