On Mon 24 Jun at 13:58 Danny Keogh (3:633/158) wrote to Meng-Shi Lim:

 ML> Another question: on a 28.8k modem, if the connection 
 ML> is made at less than 28.8k (eg 21600), can the modem 
 ML> pick up and renegotiate a higher speed from this point 
 ML> onwards if the quality of the line improves? (Personally 
 ML> I don't think so but you'll never know). I know that 
 ML> the modem can retrain up and down from the connection 
 ML> speed (eg 21600 -> 19200 ->21600) but I'm not sure about 
 ML> the above.

 DK> The connect speed is the highest speed the modem will go 
 DK> too.  It can move anywhere down from this speed.   If 
 DK> you want a higher speed, you have to hang up and ring again.

Yes, a pair of V.34 modems can increase their DCE-DCE speed after the
initial connecct.

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