A comprehensive method for handling telephone calls directed to a telephone number of a terminated user that has been reassigned to a new user. The sites of introduction and withdrawal and the site of division between the two groups of columns are all rotated around the circuit as in conventional SMB chromatography, but the process is capable of separating component mixtures with non-linear isotherms and of extracting solutes that are very strongly retained on the solid phase. The system also includes a statistics module to obtain a value of a statistical confidence-level parameter that is associated with a particular confidence level, and a pass range module to obtain a pass range of signal strengths from the value of the statistical confidence-level parameter and the n1 target signal strengths. The washstand unit 10, the waste storage compartment 11, the mirror 12, the upper cabinet 13 and the lighting equipment 14 are mounted independently on the side panel 5 without assembling. The position sensing detector has a photo-response non-uniformity of less than 2% and a position detection error of less than 10 \u03bcm across the active area.