A bandpass filter comprises a number of resonators which are arranged between an input and an output of the filter and which are interconnected to form at least two main signal paths that lead from the input to the output. The present disclosure further discloses a device for managing release of a network port of a mobile terminal. The usage compliance mechanism includes a file system filter driver for controlling data reads associated with the computer readable media. The handle has a structure to allow a position of the guide catheter to be controlled by some or all of three fingers of one hand of an operator of the handle. A magnetic device is provided to keep the rotor at positions where the aperture is fully opened and closed, respectively, even when the current to the coil is interrupted. The system has an ultra-compact construction, ideally suited for space-constrained retail scanning environments, and requires no moving parts.