The present invention utilizes wafer acceptance testing equipment to fast monitor the quality of an insulation layer. The first shaft rotatably supports the trigger member on the rotation detector, so that the rotation detector detects a rotation of the trigger member. Then, the method includes gradually decreasing P-off and gradually increasing P-on until slipping of the off-going clutch is detected, and gradually and more slowly decreasing P-off and gradually more slowly increasing P-on until the oncoming clutch begins to carry torque previously carried by the off-going clutch. The first and second lens groups are located such that of axial air spaces in the converter lens portion, an air space between the first lens group and the second lens group is largest. The portable fob further includes a second local data transceiver for receiving the predetermined aiding data from the first local data transceiver. When the measured ERL reduces to a minimum value required to perform double-talk detection, the reduction in attenuation is stopped.