User's Manual
The modem can send a string of information to the DTE consisting of supported options using the following
command:
+MS=?
The response is:
+MS: (list of supported <mod> values), (list of supported <automode> values), (list of supported
<min_rate> values), (list of supported <max_rate> values), (list of supported <x_law> values), (list
of supported <rb_signaling> values)
For example,
+MS: (0,1,2,3,9,10,11,12,56,64,69), (0,1), (300-33600), (300-56000), (0,1), (0,1)
Subparameter Definitions
1. <mod>= A decimal number which specifies the preferred modulation (automode enabled) or
modulation (automode enabled) to use in originating or answering a connection. The options are:
<mod> Modulation Possible Rates (bps)1 Notes
0 V.21 300
1 V.22 1200
2 V.22 bis 2400 or 1200
3 V.23 1200 See Note 2
9 V.32 9600 or 4800
10 V.32 bis 14400, 12000, 9600, 7200 or 4800
11 V.34 33600, 31200, 28800,
26400, 24000, 21600, 19200, 16800,
14400, 12000, 9600, 7200, 4800, or 2400
12 V.90 56000, 54677, 53333, 52000, 50669,
49333, 48000, 46667, 45333, 42667,
41333, 40000, 38667, 37333, 36000,
34667, 33333, 32000, 30667, 29333,
28000
56 K56flex 56000, 54000, 52000, 50000, 48000,
46000, 44000, 42000, 40000, 38000,
36000, 34000, 32000
64 Bell 103 300
69 Bell 212 1200
Notes: 1. See optional <automode>, <min_rate>, and <max_rate> subparameters.
2. For V.23, originating modes transmit at 75 bps and receive at 1200 bps; answering modes transmit at
1200 bps and receive at 75 bps. The rate is always specified as 1200 bps.
The modem may also automatically switch to another modulation (automode), subject to the following
constraints:
a. The modem may not be able to automatically switch from the current modulation (specified by
<mod>) to some other modulation. For example there is no standard way to automode from Bell
103 to V.23.
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