Many retail check-out stations are composed of a PC-based POS terminal. This means that the "cash register" is actually a PC that has a number of peripherals attached to it. In this case, a keyboard, a cash drawer, a receipt printer, a coupon printer, a card reader, a scale and two pole displays--one attached directly to the register, and a larger flat panel one mounted separately. Because of the small size of such an embedded system, Low Profile PCI boards are an ideal solution, because of the minimal space they require for installation. Using a single port RS-422/485 board also saves space, because a single onboard port can be used to control up to 10 peripheral devices.