>I was wondering....I'm up in Canada - and don't have the ability to test
>this, but I was wondering if anyone has ever tried making a long distance
>28.8kbps connection over AT&T Truevoice lines? How does this 'treatment'
>affect the connection?
TrueVoice is basicly a putting an equalizer in the telephone circuit,
just like the one you have on your home stereo. This is bad (very, very bad)
for higher speed protocols such as V.34.
The ANSam tone transmitted by the answering V.34 modem
contains phase reversals every 450ms. These phase reversals tell the
telephone network equipment to disable any echo cancelers in the circuit. On
lines with TrueVoice they are also supposed to disable the equalization, so
having TrueVoice on a line shouldn't bother V.34 calls.
At this time I have heard conflicting reports on whether or not the
TrueVoice equalization is actually being disconnected when phase reversals are
detected in the ANSam tone.