Yes, but chances are that you have asked the wrong question. The function is named unicode2native(), and in the case of translating to US-ASCII, what it mostly does is convert any character outside the range decimal 0 through decimal 127 in to the value decimal 26 (intended to signify that US-ASCII has no way of representing the corresponding character.)
ASCII is really a pretty restricted set of values. The question does get interesting, though, if you do not restrict yourself to US-ASCII and start wanting to do things like translate the "national currency symbol" of UK-ASCII vs US-ASCII vs the symbols used in the Scandinavian languages...
