Barcode Scanner Emulator
Barcode Scanner Not Working
A scanner that produces no input at all almost always traces back to one of a small number of causes. Work through them in order rather than guessing.
Problem
You scan a barcode and nothing happens: no characters appear anywhere, no error, no visual feedback at all.
Possible causes
- USB cable, port, or Bluetooth pairing issue — the scanner isn't actually connected
- Scanner is in the wrong mode (e.g., serial/COM instead of HID keyboard mode)
- No application field currently has keyboard focus
- Scanner's decode engine can't read the specific barcode (damaged label, unsupported symbology, poor lighting)
- Prefix/suffix misconfiguration causing input to be silently swallowed by the target application
How to diagnose
- Open a plain text editor (Notepad, TextEdit, or a terminal) and click into it so it has focus.
- Scan a known-good barcode. If nothing appears here either, the problem is the scanner/connection, not your application.
- If text does appear in the text editor, the scanner and connection are fine — the issue is specific to your application. Continue with Scanner Works in Notepad but Not POS.
- Check the scanner's activity indicator (usually a beep or LED flash) during the scan attempt to confirm it is actually reading the barcode at all.
How to fix
- Reconnect the USB cable or re-pair Bluetooth, trying a different port if available
- Scan the manufacturer's "factory defaults" or "HID keyboard mode" configuration barcode to reset the scanner's communication mode
- Click into the intended field before scanning, or add focus-restoring logic to your application if scans commonly happen after a UI transition
- Verify the barcode format is enabled on the scanner (some scanners ship with certain symbologies disabled)
How to verify
Once the scanner produces output in a plain text editor, confirm your web application receives it correctly using the Barcode Input Tester.