Regarding patent US7873522 (Measurement of spoken language training, learning and testing):
I would like to know why dependent claim 18 begins "The method of claim 17..." when claim 17 is not a method claim. Claim 17 is an apparatus claim, and does not, from what I can see, contain any method.
"17. An apparatus comprising: a user interface to receive...."
"18. The method of claim 17, further comprising a computing device to play a benchmark audio..."
The other two dependent claims that follow claim 18 (19 and 20) both begin, "The apparatus of claim 17...", as one would expect.
Wikipedia seems to indicate that a dependent claim can have a different "claim type" that the independent claim that it falls under:
Under the European Patent Convention, when a claim in one particular category (see below), e.g. a process claim, depends on a claim from a different category, e.g. a product claim, it is not considered to be a dependent claim but an independent claim. Under U.S. law, this is still counted as a dependent claim, regardless of the class change.
However, I can't understand why there is a "class change" in this case.