Acer V.90 Manuel D'utilisation page 11

Note: +F34=? ---- +F34=<maxp>[[,<minp>],<prefc>] will report the
current values for the parameters.
Parameters Function
maxp: The maximum allowed primary data rate in multiples of
2400 bps. The valid range is 0 to 14 inclusive, 0 means that
the modem will choose the maximal rate possible.
minp: The minimum allowed primary data rate in multiples of
2400 bps. The valid range is 0 to 14 inclusive. 0 means that
the modem will choose the rate.
prefc: The preferred control channel data rate in multiples of
1200 bps. The valid values are 0, 1, and 2, 0 means that the
modem will choose the rate.
9