A method for link bandwidth management between two devices in communication through a bandwidth-adjustable bus in a computer system determines which of a speed negotiation priority and a width negotiation priority is higher when the change condition is activated. By virtue of the present invention, the automatic digital-imaging based code symbol reading system ensures the reliable reading of code symbols graphically represented in digital images, in high-throughput point-of-sale and other environments. The adhesive portion is entered into a gap between the doughnut-shaped magnetic core and the bottomed container and a gap between the bottomed container and the conductive lead portion in a range of 5 to 50% in average to a thickness of the doughnut-shaped magnetic core.