Rockwell RCV144ACx, Command Reference Manual

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AT Command Reference Manual
3-40 1048
In V.34 modems if MNP10-EC is enabled manually (using AT-SEC=1) no particular modulation will be chosen, therefore if
the user wishes to force V.32bis modulation they should use the AT+MS=10,1,minspeed,maxspeed command (e.g.
AT+MS=10,1,4800,12000 would force V.32bis and limit the speed between 4800 and 12000 bps). To allow V.34 modulation
use AT+MS=11,1,minspeed,maxspeed (e.g. AT+MS=11,1,4800,19200 would allow V.34 speeds between 4800 and 19200).
When MNP10-EC is enabled in V.34 modes the symbol rate is limited to 3000, therefore the maximum speed would be
26.4K however the initial connect speed is limited to 21600.
If an AXCELL™ solution is used, a transmit level of -10dBm is required, therefore the following init string should be used:
Cell Site AT &F -SEC=1,10
It is recommended that systems be set up if possible with separate modems to receive calls from other land based modems
and cellular modems. This is so that land based users that experience high network attenuation do not have connection
problems when communicating to modems configured for cellular operation.
The above configurations are the minimum additional AT commands may be issued to change the result messages etc,
AT&F is used to ensure that the modem is in a know state.
Table 3-2 summarizes the mode and resulting transmit levels for both modems depending on their configuration.
Fax Configuration
It is recommended that fax transmissions be configured to operate at 9600 bps in V.17 mode or 7200 bps in V.29 mode.
Cellular Phone Configuration
To achieve the best operational performance, a cellular data connection should be attempted in a location where adequate
signal strength is observed for the cellular phone. This condition can be easily monitored on some phones with signal
strength indicator. In locations where even voice calls are unreliable, data connections should not be attempted. Under some
circumstances a special high gain antenna may improve performance.
Additional information regarding the use of the cellular phone and cellular network should be obtained from the service
provider and or cellular phone manufacturer.