There are two methods you can use to use a programmable keyboard with the Cloud Retailer POS. Please follow the procedure below.
1) You can assign F keys to each POS button and then fire that F key through the custom POS button. This option is very simple but is also quite limited.
2) You can embed a command into the keyboard that executes that function on the POS, regardless of the buttons you have set up. The same way you program a button to execute a command you can fire the command directly from the programmable keyboard - the command text and structure is the same except you need to embed an "STX" character to start and an "ETX" ASCII character at the end. It works exactly the same way as embedding functionality into a barcode. You can learn more here: How to automate POS workflows (ADVANCED)
Using this functionality, you can program your keyboard to execute any function you could execute from a button.