> i2c, for instance, AFAICT
> requires a resistor next to each node the value of
> which is determined by the total number of nodes.

There is no such requirement in the IIC spec.  It does define the maximum
current any node must sink to drive a bus line low (3mA if I remember
correctly).  IIC is usually implemented between parts on the same board.
In that case you can usually ignore transmission line effects and provide
a pullup at a single point.


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