"DoN. Nichols" wrote in message
...

Certainly not the kind of speeds which would give problems with
the signal reflections. Now when you are talking 10 MHz or faster,
then
it really matters. :-)

Enjoy,
DoN.

What really matters is the length of the signal path measured in
wavelengths at the max operating frequency. If the line is short
enough that you can't see any phase shift in reflections from the far
end then you can consider it a single 'lumped element', if you can
then it's a transmission line.

As a rough rule of thumb electricity travels about 6" or 150mm per
nanoSecond on a circuit board, about half the vacuum speed of light.

You know you are deeply into high technology when the time light takes
to travel one millimeter becomes important to you.

-jsw