PE> From first glance at the V34 spec, I have a theory
PE> that the levels reported by the USR are dependant on the
PE> frequency and symbol rate the remote modem chooses to use.

Nope, that graph is the analysis of the line characteristics, also
called the line probe, BEFORE the modem chooses the carrier frequency
and the symbol rate to be used, and is WHAT the modem uses to CHOOSE those.

The whole point of V34 is that it MEASURES the line and uses the values
it measures to determine what values for the adjustable parameters to use.
Those include the frequency of the carrier, the symbol rate, and a wide
variety of other stuff like the transmit level, the shaping, pre-emphasis etc.

PE> BTW, the spec says that the remote modem uses a 600 ohm
PE> pure resistive load (my interpretation of the spec, anyway).

It cant work like that with an echo cancellation protocol coz you cant
cancel the echo of what you are sending out properly if you have too much
of a discrepancy between the load the modem presents to the line and the
impedance of the line itself. For hard to explain reasons, you have a problem
with the hybrid working properly echo cancellation wise if you do that.

Tho thats certainly the norm that you work from.
@EOT:

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