If your printer or cash drawer isn't working, you can check if it's connected properly to your network. This can be done with the CUPs web interface.
Check if your device is connected
1 Open your browser and copy this address: http://localhost:631/printers/
2 This is what it looks like if the printer or cash drawer is connected.
3 This is what it looks like if the printer or cash drawer isn't connected.
Add your device
1 To add it, go to the magnifying glass at the top right-hand corner of your screen.
2 This will open up a spotlight search. Search for Terminal.
3 Copy "cupsctl WebInterface=yes" and paste into the terminal window. Click Enter.
4 Close the window and refresh your browser screen. Your printer or cash drawer is now connected.
If it still does not appear, you may need to reinstall the driver of the printer or cash drawer. Go to the device's website for detailed instructions on how to reinstall it.