Appeal No. 2002-1318
Application No. 08/693,662
appellants specification discloses (page 6), with respect to
figure 1, that:
If node N1 has a message for node N5, the message must be
transmitted through the source 13. The source 13 typically
involves a transformer or the like which does not provide an
effective transmission path for a data signal having a frequency
much higher than the power frequency. For instance, where each
node includes a transceiver such as manufactured by Echelon
Corporation, part no. PLT-20/21, signals are transmitted between
the nodes at a frequency (when compared to 60Hz) of 131.5789kHz.
This relatively high frequency is in some instances not
effectively transmitted from line 14 to lines 15 or 16 through a
transformer.
We find from this disclosure of appellants that it was known
to transmit signals between the nodes of power lines at a high
frequency, e.g., 131.5789kHz (i.e. 132kHz). The specification
additionally discloses (id.) with respect to figure 2 that "these
lines are not connected in a way that permits effective
distribution of a high frequency (e.g., 132kHz) communications
signal," and that (page 7) “[t]he RF receivers 24 and 25 may be
ordinary radio frequency receivers tuned to receive signals of
the frequency of the communication signal in the network (e.g.,
132kHz).”
From the disclosure that the transmitted signal is at 132kHz
and that the signals picked up by RF receivers 24 and 25 is
132kHz, we find that the signals transmitted between the nodes of
14
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