Achieved bandwidths for existing subscribers are collected and organized into a statistical bandwidth table utilizing characterizing information, such as the Central Office that provided the service, the type of xDSL service that was provided, the primary, secondary, and other cable segments over which service was provided, and the subscriber loop length increment. The backframe is configured by interlinked linkages such that the backframe can be locked in a fully extended position in use, or be collapsible when not in use in a way that the overall dimension of the collapsible backframe is smaller than the fully extended backframe. A first audio acquisition device is at the end portion or in the main body. The apparatus further includes the fluid-proof keyboard, which is submerged in the fluid-filled structure proximate to the computer and which is coupled to the computer to provide for manual keyboard input to the computer. The preheating shaft of the melting furnace and the tapping portion have a distance between the mutual part, so that scraps do not flow out on a the tapping hole side. Impedances associated with sampling semiconductor switches are maintained substantially constant during sample states, at least in part, by compensating for encountered input signal variations in order to reduce or minimize signal distortion associated with sampled signals that pass through the sampling switch.