FIGS. 5 and 6 are a rear view (if the casing 30 is wall-mounted) or bottom view (if placed horizontally on a table or shelf), and a side view (where wall-mounted), respectively. These show the main unit 32 as having a round, flat base wall 42, and the opening 39 for the power cord formed at one edge where the base wall 42 meets the cylindrical side wall 36. In the embodiment as shown here, the opening 39 for cord 22 is at the rear in a horizontal table placement, but would then be at the top if the unit is wall-mounted. If it is desired to run the cord 22 downward, e.g., from the lower side of the casing or housing when wall-mounted, a means for passing the cord 22 downward may be formed in the wall 42 and one example is discussed below in reference to FIG. 8. As also shown here, there may be holes 46 formed in the back wall to permit the use of screws or other fasteners to attach the base main component 32 to the wall. Or if preferred, a double-sided adhesive tape or similar material may be used for attaching the main component 32 to the wall.