Barcode scanners.

Any USB barcode scanner that types like a keyboard works: plug it in and scan on the Sell screen.

Set the scanner to send Enter after each barcode (most do). Settings, Hardware, Scanner shows what ARC OS sees.

Scanning still works when the Sinhala (Wijesekara) or Tamil keyboard is on: ARC OS reads the scanner by its speed, not by the letters.

A 2D scanner also reads QR codes, including your bank's LankaQR sticker (Settings, Customer display, LankaQR code text).