“Host interface,” in claim for PDA module requiring use of “host interface adapted so as to provide communications” between PDA and host computer is properly limited to “direct parallel bus interface” based on: 1) the limited description of “host interface” in the specification; 2) the emphasis in the specification placed on the importance of parallel connection in solving problems associated with serial connections; 3) the more inclusive description in the specification of another interface on the PDA module as providing either a parallel or serial interface; 4) identification of the direct parallel bus interface as being a “very important feature” of the invention; and 5) arguments made during prosecution and on appeal to the Board distinguishing prior art based on Applicants’ assertions regarding the recited “host interface” as being a direct parallel bus interface.