The cash drawer will not open: cable, command or lock

Check three causes in order: the key lock set to closed, an RJ cable plugged in somewhere other than the printer’s DK port (often a network port that looks like it), then software that does not send the open command. The key test rules out the first cause in a few seconds.

Level: field setup

Have ready: The drawer key and access to the printer configuration in the client’s point-of-sale software.

Procedure

1. 1

   Test the lock with the key

   If the drawer will not open with its key, the problem is mechanical. The lock usually has a position that blocks the electric release while still allowing manual opening: it is the most common cause of this symptom.

2. 2

   Check which printer port is used

   The cable must be in the port marked DK or Drawer. An RJ connector fits perfectly into the Ethernet port and triggers nothing there. Unplug and replug the cable, going by the port label.

3. 3

   Trigger the opening outside the software

   Many printers can kick the drawer from their configuration utility. If it opens there but not from the till software, the cabling is fine and the fault is a software setting.

4. 4

   Check the software’s open-drawer setting

   The software decides when to send the pulse: on cash payments only, on every sale, or never. A client reporting that “the drawer stopped opening” has sometimes just changed payment method.

5. 5

   Cross-test with another drawer or printer

   Plug the drawer into another printer known to be good, or another drawer into this one. That is the test that identifies the failing part, and the first information asked for when opening a return request.

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Guide revised on September 22, 2026