Cash drawer guide: connect it so it opens on every sale
Last updated: 3 October 2026
Most cash drawers don't connect to the tablet or PC but to the receipt printer. When a sale is rung up, the printer sends a pulse and the drawer opens. Here's how to connect it and what to do if it stays shut.
How it works
The drawer cable ends in a small RJ11/RJ12 plug (like a phone plug). It goes into the "DK" or "Cash drawer" port on the back of the thermal printer, so the printer must be connected and working for the drawer to open.
Tested with PosSwift: APG Vasario VB320, opened by the printer over RJ12, with cash and cheque slots.
Connecting it
- Plug the drawer cable into the printer's DK port (not a network port: the plug looks similar but doesn't belong there).
- Check that the printer prints normally (self-test page, then a receipt from PosSwift).
- Ring up a test cash sale: the drawer should open as the receipt prints.
- Keep the drawer key: it opens the drawer by hand in a power cut and locks it at night.
It won't open
| Symptom | Likely cause | Fix |
|---|---|---|
| Receipt prints, drawer stays shut | Cable in the wrong port | Plug it into the printer's DK / Cash drawer port |
| Nothing happens at all | Printer not connected | Fix printing first (see the printer guide) |
| Never opens, even by hand | Drawer locked with the key | Turn the key to the open position |
| Printer has no DK port | Some small printers lack one | Choose a printer with a drawer port, or a manual drawer |
With PosSwift
PosSwift works with printer-driven cash drawers, and its day close totals the takings so you can compare them with what's in the drawer.
- Guide: receipt printer
Choose, connect, troubleshoot.
- Guide: barcode scanner
Choosing and connecting a scanner.
- Discover PosSwift
Offline point-of-sale for Moroccan shops.