Appeal No. 2001-2270
Application 09/235,529
the path that was taken by the applicant." In re Gurley,
27 F.3d 551, 553, 31 USPQ2d 1130, 1131 (Fed. Cir. 1994). The
alternative or additional use of a waveform generator does not
constitute a teaching away from using the attenuator alone to
block the DTMF tones. The waveform generator teaching does not
contradict Stevens' teaching that the DTMF signals should be
attenuated so that they are not detected by the central office.
Appellants argue that the attenuation of dialing signals by
more than 30 dB by the present invention requires that highly
attenuated DTMF dialing signals be detected by the transmission-
inhibiting device of the present invention even though such
signals cannot be detected at the central office. It is argued
that this engineering task of processing substantially attenuated
dialing signals is not addressed by Stevens at all, which "is
presumably why Stevens teaches away from the techniques as
recited by the present invention" (RBr5). It is argued that
"Applicants disclose a method of detecting the attenuated dialing
signals even though they are attenuated by greater the [sic,
than] 30dB" (RBr6) and it is the ability to detect these
attenuated dialing signals as in the claimed invention that
enables the user to connect it across any point in the telephone
line so that it can be used for multiple parallel devices (RBr6).
Appellants argue that if Eaton were changed to a parallel load,
the dialing signals could no longer be detected by the decoder
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