The Cash register being a commercial device uses a 9 pin RS 232 connector, these are usually found on desktop computers but not always. Laptops do not usually have these RS 232 connection either.
You can buy converters that will connect the USB to our 9 pin PC cable.
***Please note, we cannot support these products. We will help you setup you cash register but we do not know how to change the settings on the converters. You will have to setup these converters yourself.