Appeal No. 2001-2270
Application 09/235,529
Eaton could be used in a parallel attenuator such as Stevens for
the same purpose of preventing detection of DTMF tones by the
central office.
For the reasons stated above, we conclude that the examiner
has established a prima facie case of obviousness which
appellants have not shown to be in error. Accordingly, the
rejection of claims 1, 3-6, 9, and 11 is sustained.
Group II: Claims 2 and 10
Representative claim 2 recites that the load attenuates the
dialing signals by "at least 38 dB."
Appellants argue that neither of the references suggests
this level of attenuation and there is no evidence why such a
level of attenuation would be desirable (Br8).
The examiner concludes that 38 dB would have been obvious
because one of ordinary skill in the art, knowing from Stevens
that the attenuation should be selected to prevent detection of
the DTMF tones by the central office, is presumed to have had
sufficient skill to determine a specific value by routine
experimentation (EA9), citing In re Boesch, 617 F.2d 272, 276,
205 USPQ 215, 219 (CCPA 1980) ("[D]iscovery of an optimum value
of a result effective variable in a known process is ordinarily
within the skill of the art."); In re Aller, 220 F.2d 454, 456,
105 USPQ 233, 235 (CCPA 1955) ("[W]here the general conditions of
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