[plug] modems (was Re: [plug] Gut modem für Linux? [those blinkinglights again])

[BillK]

Hi Brett,
	modem modulation at 33.600 and below uses various analog techniques to
sustain the analog signal.  V.90 speeds above this actually try to use
the line as a digital line with compensation and other tricks to sustain
the signal (and lots of computational power needed at both ends).  Yes
the theoretical maximum speed of an analog line using current modem
techniques is 33.6, but this limit is bypassed whith V.90 techniqes, not
increased if you see the difference.  This makes it a little more
susceptable to noise etc, but not a lot.  Use the same techniques as for
analog, if the modem is not stable enough, force it to connect at a
lower speed that is stable.  I regularly connect at 48k (iinet modem
diags show its actually 40-45k and other direction speeds are usually
31(something)khb/s).  The line is rock solid unless thunderstorms are
around (where a lower, and analog speed works) and the speed and
response is noticeably better than 33.600, enough to waste the 25c or
whatever to reconnect in the hope of getting a faster speed!

Billk