The invention relates to a connector for clamping a component around a tubular member and to a method of using such a connector. Detent torque of the stepping motor is reduced either by reducing a cross-sectional area of a portion, which leads to a magnetic pole surface 51a of the stator yoke, to be less than an area of the magnetic pole surface 51a, or by disposing an intermediate magnetic substance 9 which is magnetically independent of the stator yokes 5a and 5b on both sides thereof. The downstream device controller adjusts its local variable optical attenuator by utilizing optical noise emission from a post-amplifier in the upstream optical transmission device, and it selects and sets a preamplifier unit to work in appropriate operating mode. The received composite symbol is demodulated using the joint constellation so as to reconstruct the data transferred from the N transmitters. The solder mask includes at least a void therein. The method described herein is particularly useful for identifying peaks in data sets obtained from spectroscopy.