Gene Fuller wrote:
I said no such thing about "black boxes" being unable to have more than
two terminals. What I said is that the "black boxes" defined by Keith
and Roy have only two terminals.

But the "black boxes" defined by me have either two
terminals or four terminals. Here they are again:

--43.4 deg 600 ohm line--+--10 deg 100 ohm line--open

--43.4 deg 600 ohm line--+--46.6 deg 600 ohm line--open

--43.4 deg 600 ohm line--+--j567 impedor

The black boxes are drawn around the '+' point just as
I said before. That makes the first two examples four-
terminal networks and the last example a two-terminal
network.

Now tell us again how s11, s12, s21, and s22 are identical
for those three black boxes.
--
73, Cecil http://www.w5dxp.com