Some NCR cash registers used this trick: they shipped with all the hardware included, but jumper blocks determined what percentage of the hardware the customer had paid for. As the customer’s business grew, they could purchase additional capacity, and an NCR service technician would visit to adjust the jumpers, instantly unlocking 25% more capacity. The actual limits were software-based; the jumper block was only read at startup or when a special code was entered on one of the terminals, and the software limits would adjust accordingly.