The disclosure is directed to an encoder apparatus that is capable of resolving magnetically axial andor rotational displacements of a knob shaft thereof independently and includes a magnetic snap action switch, and a method of assembling the same. In selecting the access request, the access requests are selected for each thread based on the specified priority control from among the access requests issued from the threads held in the port unit, thereafter a final access request is selected in accordance with a thread selection signal from among those selected access requests. The handpiece includes an irrigation valve which, when depressed, opens the valve and permits irrigation liquid to flow to the surgical site. 11 ag preamble that includes at least one short training symbol, at least one long training symbol and at least one SIGNAL field. Each CCFM can be divided into segments according to the layout of the continuous presence image that is to be displayed by one or more receiving endpoints.