> > * Aaron@Cisco.COM (Aaron Leonard) [Tue 11 Jun 2002, 21:17 CEST]:
> > > I don't think that CSCdi75794 is applicable, since it
> > > (supposedly) is specific to the 2400 bps V.34 / nonLAPM
> > > case, while Simon's problem is with 2400 bps V.22bis / nonLAPM.
> >
> > 2400 V.34 doesn't exist. V34 is 28800 bps, V22bis is 2400 bps. V34
> > modems can usually connect at V22bis speeds (i.e., 2400 bps), but that
> > doesn't make the connection V34; it makes it V22bis.
Wrong. V.34 supports speeds from 2400 bps through 33600 bps.
> > In my (limited, with these low speeds) experience, V34 modems connect
> > better/more stable at V22bis speeds than V22bis modems themselves, but
> > that's not the point here (and probably due to better electronics used -
> > time hasn't stood still inbetween those generations).
To be sure V.34 at 2400 bps in theory provides better signal quality
for a given SNR than does V.22bis at 2400 bps. However, in my
(considerable, actually) experience, it is not uncommon for V.22bis
to perform better than V.34, since V.34 does echo cancellation in
the modem ... if network echo cancellers enable, then this pretty
much blows V.34, while V.22bis is fine with this.
Aaron (who keeps a copy of V.34 on his desk) (admittedly buried rather deep)
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