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b. The DTE may disable automode operation (see <automode>
below).
c. The DTE may constrain the range of modulations available by
specifying the lowest and highest rates (see<min_rate> and <max_rate> below).
2. <automode> is an optional numeric value which enables or disables
automatic modulation negotiation using V.8 bis/V.8 or V.32 bis Annex A. The
options are:
<automode> Option Selected Notes
0 Automode disabled
1 Automode enabled using V.8 bis/V.8 or V.32 Annex A Default
The default value is 1, which enables automode. Note, however,
there are modulations for which there is no automatic negotiation, e.g., Bell 212
(<mod> = 69).
For <automode> = 0 (automode disabled, i.e., fixed modulation):
a. If <max_rate> is within the rates supported by the selected
modulation, the selected
rate is that specified by<max_rate>. For example:
AT+MS=10,0,1200,4800 selects V.32 bis 4800 bps fixed rate.
b. If <max_rate> is greater than the highest speed supported by the
modulation
specified by <mod>, the starting rate is the highest rate
supported by the selected modulation. For example:
AT+MS=10,0,2400,14400 selects V.32 bis 14400, 12000, 9600,
7200, or 4800 bps.
c. To emulate issuance of the N0S37=x command sequence to
select fixed mode operation, specify the <max_rate> and <min_rate> both to be
the (same) requested speed, and <mod> to be the modulation for that speed. For
example:
AT+MS=11,0,16800,16800 selects V.34 16800 bps fixed mode (no
comparable S37 command).
AT+MS=10,0,12000,12000 selects V.32 bis 12000 bps fixed mode
(same as N0S37=10).
For <automode> = 1 (automode enabled, i.e., automatically selected
speed and modulation):
The modem connects at the highest possible rate in accordance with
V.8 bis/V.8, or
V.32 bis Annex A if V.8 bis/V.8 is not supported by the remote
modem.
a. If <max_rate> is greater than the highest rate supported by the
modulation specified by <mod>, the modem automodes down from the highest
rate of the selected modulation. For example:
AT+MS=10,1,1200,24000 selects automoding down from V.32
bis 14400 bps.
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