Appeal No. 97-1694
Application 08/351,064
reduce power consumption because no current flows in the
termination unit 241 as long as no signal is transmitted via
the bus line 240" (page 49). Thus, we wonder whether
appellants meant to claim that no current flows in the
termination device (instead of in the bus) when no signal is
transmitted via the bus. We take the claims as we find them.
Lloyd discloses an improvement in a wire-OR bus. "These
transmission lines normally operate between high- and
low-voltage states, representing digital ones and zeros. The
bus wires are normally biased to reside at their high-voltage
states. They are selectively pulled down to their low-voltage
states by bus-driver circuits in each coupled element."
(Col. 1, lines 22-28.) "The expression wire-OR bus conveys
the concept that each wire serves as an OR-gate by changing
its state in response to any one of the bus drivers."
(Col. 1, lines 32-35.) The resistors R1 to R4 in figure 1 of
Lloyd bias the bus to a high-voltage level (col. 4,
lines 1-11). "The bus wire is pulled down to the low voltage
level whenever one of the bus driver circuits (22) in a
system-circuit element (14) connects it to ground." (Col. 4,
lines 11-14.) The bus driver 22 has a large transistor which
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