U-ScanTM is a mostly-customer-driven point of sale (POS) system invented by Optimal Robotics (www.optimal-robotics.com). So far, over 5,000 terminals have been installed, and the company offers three variations: the "express," the "carousel," and the "solo," which is designed for convenience stores and other space-limited businesses. The appeal of U-Scan lies in the fact that the customer does most of the work, which reduces cashier labor costs and "increases convenience." A single attendant must be present at all times, but they can effectively run three "express lanes" (U-Scan terminals are usually intended for checking and bagging fifteen items or less in my experience) at once.
The system works using electronic scales, a barcode reader, a touchscreen computer (running Windows, although I'm not sure which version), a bill acceptor and changer, and a card reader. When you scan an item, you must promptly put it into a bag, where it is weighed and tallied. The most annoying thing about the system is that it "defaults" to plastic bags, which are already accounted for on the scales. If you try to use a paper bag, it will immediately detect the change in weight and sieze. Even if you put the bag on before you even hit the first button, it will bitch you out.
If you remove an item from the bag, or try to scan another item before putting the previous item away, the machine will stop working until an employee sees what's going on. If you try to buy cigarettes or alcohol, it will halt until an employee sees your ID. All in all, it runs smoothly, assuming the people ahead of you know how to use it. It gets really tedious when all of the machines are tied up with people who've never used them before. There are doubtlessly many ways to defraud the U-Scan machine, although the only method I've discovered thus far involves organic produce (see the link if you're absolutely riveted by my passionate description of U-Scan and would like to know how you purchase produce with it).