Wireless data communications using a masterslave protocol are easily established between a master radio module which is part of a POS terminal and a slave radio module which is part of a portable bar code scanning device. The separator includes stationary vanes in a cylindrical housing to establish a cyclonic flow therethrough, an annular flow restriction collar to establish a liquid collection area at the downstream end of the housing, a drain for discharge of the liquid from the collection area, and a flow interrupter to direct the swirling liquid into the drain. In a testing procedure, the air-fuel ratio is monitored under various conditions of the air pump and the value to determine whether the valve has failed to open or close and whether the pump has failed to start or stop. A second die is opposed to the first die while supporting a second face of the plate member.