While sitting on cloud 9, Michael Raiteri said to all something about 
    Modem connect speed

 MR> Hi, 
 MR> 
 MR> Can anyone tell me if there is a way to force a Rockwell based 
 MR> modem to connect at a certain speed eg 24000 or 26400. 


 MR> I know that ATN0S37=11 will force a 14400 connect but that seems 
 MR> to be the highest forced connect rate I can find anywhere in the 
 MR> manual. 
 MR> 
 MR> USR based modems are able to set a maximum and minimum connect 
 MR> speed and I want to know if Rockwell based modems have the same 
 MR> capability secretly hidden. 
 MR> 
 MR> Any help would be appreciated. 

This came of the web site for my modem [v.34] which uses the
rockwell chip set.

Hope you can make some sense of it.
............................................................


LIMITING THE MODEMS TOP SPEED

If you experience problems connecting to slower modems (2400 or 1200bps),
you may need to instruct your modem to limit the top speed to attempt. You
may also need to limit the top speed the modem attempts to something less
than 28,800bps, even when calling another 28,800 modem, because of the line
noise in your area. If you don't, you may experience "garbage" or
a "NO
CARRIER" message.
This should not be neccassary in most cases, but, there are some 2400bps and
1200bps or even 9600bps modems you may not connect to without using one of
the following methods:

Note: Rockwell has changed the method of limiting the top speed. There is now
      one method that should be used in most cases. The older method of using
      the N0 command and setting S37 to a value will still work for speeds
      under 14,400, but the S37 settings above 14,400 that were used by the
      V.FC chipset will not function. The Fn command has also been eliminated
      and replaced with the +MS= command.

1.    Use the +MS= command. AT+MS=11,1,19200,24000 will set the modem to use
      V.34 modulation, automode detection, with 19200bps as the lowest
      connection rate acceptable, and 24,400 as the highest connection rate
      attempted. AT+MS=11,1,2400,24000 will set the modem to use
      V.34 modulation, automode detection, with 2400bps as the lowest
      connection rate acceptable, and 24,000 as the highest connection rate
      attempted.
      Note: See the +MS= command for more details and examples.

2.    Use the combination of the N0 command along with setting S37 to the
      proper value to limit the modems connection speed attempted.
      
3.    Use the N0 command and set your software to the connection rate
      desired.
      Note: This is not the desired method to use if you are making an
            error-correction connection with compression! The softwares
            "BAUD" rate should be at least twice, and preferably
four, times
            the Carrier rate established. Otherwise you will get no benifits
            from the compression. Transfers will actually be slower than if
            a non-compression connection was established. You also cannot set
            software to all the connection rates that are supported by the
            V.34 28,800 modem.


AT+MS      Select Modulation
This extended-format command selects the modulation, optionally enables or
disables automode, and optionally specifies the lowest and highest connection
rates using one to four subparameters. The command format is:
          
         
+MS=<mod>[,[<automode>][,[<min_rate>][,[<max_rate>]]]]<CR>

Notes:
1.  For 14400 bps and lower speeds, the Nn command and S37 register can
    alternatively be used, in which case the +MS subparameters will be modified
    to reflect the Nn and S37=x settings. Use of the Nn and S37=x commands is
    not recommended but is provided for compatibility with existing
    communication software. (S37 is not updated by the +MS command.)
2.  Subparameters not entered(enter a comma only or <CR> to
skip the last
    subparameter) remain at their current values.

Subparameter Definitions

1.  <mod> = A decimal number which specifies the prefered
modulation (automode
            enabled) or the modulation (automode disabled) to use in
            originating or answering a connection. The options are:

<mod>  Modulation    Possible Rates (bps) {see note 1}
  0      V.21            300
  1      V.22            1200
  2      V.22bis         2400 or 1200
  3      V.23            1200         {See note 2}            
  9      V.32            9600 or 4800
 10      V.32bis         14400,12000,9600,7200, or 4800
 11      V.34            28800,26400,24000,21600,19200,16800,14400,
                         12000,9600,7200,4800, or 2400
 64      Bell 103        300
 69      Bell 212        1200
 74      V.FC            28800,26400,24000,21600,19200,16800, or 14400
Notes:
1. See optional <automode>,<min_rate>, and
<max_rate> subparameters.
2. Not supported by Zoltrix V.34 Fax/Modem.

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 or V.32bis Annex A. The options are:

<automode>   Option Selected
  0          Automode disabled
  1          Automode enabled using V.8 or V.32 Annex A

  The default value is 1, which enables automode. Note, however, there are
  modulations for which there is no automatic negotiation, e.g., Bell 212.

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:

        +MS=9,0,1200,4800   selects V.32 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:

        +MS=9,0,2400,14400  selects V.32 at 9600 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:

        +MS=11,0,16800,16800   selects V.34 16800 bps fixed mode
        (no comparable S37 command).

        +MS=9,0,12000,12000   selects V.32bis 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, or
V.32bis Annex A if 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:

         +MS=10,1,1200,24000  selects automoding down from V.32bis 14400 bps.

b. To emulate issuance of the N1S37=x sequence command, specify the modulation
   and the rate to start automoding down from using <mod> and
<max_rate>,
   respectively. Set <min_rate> to 300 to allow automoding
all the way down
   to V.21 300 bps. For example:

         +MS=11,1,300,16800  selects automode starting at V.34 16800 bps
         (no comparable S37 command).

         +MS=9,1,300,12000  selects automode starting at V.32bis 1200 bps
         (same as N1S37=10).

3. <min_rate> is an optional number which specifies the
lowest rate at which
   the modem may establish a connection. The value is decimal coded, in units
   of bps, e.g., 2400 specifies the lowest rate to be 2400 bps. The default
   is 300 for 300 bps.

4. <max_rate> is an optional number which specifies the highest rate at
which
   the modem may establish a conection. The value is decimal coded, in units
   of bps, e.g., 14400 specifies the highest rate to be 14400 bps. The default
   is 28800 for 28800 bps.
............................................................


That's a section out of the manual for my modem.  Hope you can
make sense of that 'cause I bloody can't.


THE FURBALL:  FURBALL{at}STRUG.COM.AU
"The fur will be with you, always."
------------------------------------------------------------

... Excuse me, I have to recharge my flamethrower.
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