CUPS (formerly known as Common UNIX Printing System), is a network printing system that allows Mac OS devices to connect to various printers on a network, including Cash Drawers.
As the CUPS Web Interface may be disabled by default on your Mac, you will need to enable it in order to have your Thermal Receipt printers appear on the network.
To do this, you will first need to visit:
http://localhost:631/printers/ .
A screen will then appear saying Web Interface is Disabled. An indication that CUPS has been disabled on your particular Mac device.
To enable CUPS:
Select and copy ‘cupsctl WebInterface=yes’ from the page.
Then, use the search box in the top-right hand corner of your screen, and search for Terminal.
Once you are in Terminal, paste (Ctrl + V) in ‘cupsctl WebInterface=yes’ and hit Enter.
Now, once you go to http://localhost:631/printers/ you will see your installed printers.
To change the settings for your printer (or the cash drawer) click the desired printer.