PE> Yeah, in the absence of some scientific evidence
PE> from Rod about why modem's impedence is constant,
PE> the guesses seem equally as valid, yours more so.

RS> Welp they aint, tho in your case you can be excused because you
RS> dont know that much about the finer detail of electronic hardware.

RS> The short story is that the 'modem impedance' cant be anything, and
RS> is in fact under the control of the modem with a modem echo cancelling
RS> modem. Its not that easy to summarise the detail in a para or two,
RS> but there is a thing called a hybrid which combines the receive and
RS> transmit onto the single pair of wires that are the phone line. How
RS> well the modem can cancel out its OWN outgoing data so it can here
RS> the data from the other end at all, and remember they are on the
RS> SAME frequency with modern modems, depends on how close the modems
RS> impedance is to the lines impedance for complicated reasons. And
RS> thats why you see the near end and far end echo figures in the
RS> stats, they are a measure of that impedance imbalance.

PE> [and later]

RS> Well, its a bit more complicated than that when the modems can vary
RS> the impedance they present to the line to balance the hybrid. Part
RS> of what So Bills waffle about modem impedance is just that, waffle.

PE> Looks like another fence-jump to me, Rod.

Welp, you had better get your glasses checked, coz it aint.

PE> Sure, I may be misunderstanding you, but that's the way it comes across.

Only if you know fuck all about the fine detail.

PE> Your theory was that the impedance doesn't change,

Never said anything remotely like that.

PE> you then say it "can't be anything" (why not be more definitive
PE> and say "is always constant" so we know you're not jumping fences),

Because I AM NOT SAYING ITS ALWAYS CONSTANT YOU FUCKING DORK.

PE> then you say "it's under the control of the modem",

Which is no problem if I never said its
constant, just some dork claims I did.

PE> and then you finally come out and say that "modems can vary the impedance
PE> they present to the line", which is exactly what Bill was saying.

Nope its NOT what Bill was saying AT ALL.

Lets go thru it again, for those who dont understand
the basics, but still are prepared to make fools of
themselves trying to tell ME what I am trying to say.

The impedance of the PHONE LINE at the wall socket varys considerably.
Primarily due to stuff like the length of line between there and the
phone exchange and the type of wire used, and other stuff like that.

Because a phone line has just two wired, and BOTH modems are transmitting
on those two wires simultaneously, you need a thing called a hybrid to
separate those two wires into the receive and transmit sides of the modem.
You also need to have the IMPEDANCE OF THE HYBRID reasonably close to the
impedance OF THE LINE otherwise you cant do echo cancellation, cancelling
the transmitted signal you are sending out so you can hear the other modem.

That means that the Netcom CANT be wildly different impedance
to the Courier, otherwise the hybrid wouldnt work. So you cant
blame the discrepancy in the stats with a Netcom on that.

AND there is a separate measure of the hybrid impedance
mismatch in the near end and far end echo figures in the
stats as well, which ALSO show that the Netcom isnt a
considerably different impedance to the Courier.

PE> I'm just telling you how your messages come across TO ME sometimes,

I cant help it if you are ignorant of the technical details and just
to silly conclusions because you are Paul. Your problem entirely.

And a rather graphic commentary on your analytical skills too.

PE> and I bet they come across TO BILL exactly the same.

I couldnt basically give a shit how they come across to Bill,
he isnt even capable of rationally considering the question of
how USR does the ATZ command and reaching a sensible conclusion.

The 'one of the most racist countrys on earth' is an even more graphic example.

PE> If your goal is to communicate, you have a problem.

Bullshit I do, YOU have a problem pontificating from UTTER ignorance
of the technical fine detail of modems Paul. You know so little about
it you think you see fence jumping when in fact the only problem is
that you know sweet fuck all about what is being discussed.

And lets not try pontificating on effective
communication, you are one of the worst at it yourself.

PE> Who is violating the English language spec is
PE> a different story, could be me+Bill, could be you.

Its got nothing whatever to do with the english language, everything
to do with your ignorance of what is being discussed which leads you
to the conclusion you are seeing fence jumping when in fact you are
actually seeing your ignorance instead. Your problem, not mine.

PE> I find it hard to believe that the USR Courier can conform to
PE> the V.34 spec AND simultaneously decide that the other end is
PE> a non-Courier so it should start faking away at the numbers.

RS> Thats just playing silly buggers. No one is suggesting that
RS> it does that on purpose. Its clear from the MASSIVE difference
RS> of 6db, which is a HELL of a fucking lot, that it claims to
RS> see with and M34F on the other end, its having a massive brain
RS> fart. Just why is currently harder to say. One obvious possibility
RS> is just a bug in the USR code in that particular situation.

PE> In what particular situation?

With a rockwell V34 on the other end.

RS> It would be interesting to see what happens with a
RS> non rockwell non USR on the other end, like a Motorola.

PE> To keep the test consistent would mean using
PE> my phone line, which means I need the Motorola,

Yes, thats what I meant. Or you could for example find a line with
a Motorola, get the stats when calling it with a Courier, replace
it with a Courier, see if the stats change significantly. Ideally
put a rockwell V34 on there too, see what stats you get too.

Its not critical to use you particular phone line as
long as you can see that big difference between Courier
and rockwell on whatever line you chose to look at.

PE> so that test can't be done accurately.

Depends entirely on whether you can borrow a Motorola or not.

PE> I guess if we're guessing, we should ask the question, if YOU
PE> were designing a modem, how would YOU measure the line quality.

(Continued to next message)
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