A method according to one embodiment may include receiving one or more packets from at least one external device and storing one or more packets in at least one queue in memory, the memory includes a plurality of queues and a plurality of queue descriptors having pointer information to point to a queue. The lens action is achieved by magnetic fields, which fields are generated by permanent-magnetic materials. In one embodiment, the digital control circuit implements a binary jump method and an operating curve is selected when the operating curve has an output frequency meeting the target frequency with the control voltage being within a first voltage range being a narrowed and centered voltage range within the control voltage range. A second substrate has a plurality of second conductive vias formed partially through the second substrate. Other embodiments are also described. The control unit includes a determining part for determining an accelerating state of the vehicle engine, a detecting member which detects a thermal load of the evaporator, a setting part for setting a minimum control value in accordance with the thermal load, and a controlling part.