Synxcom SM9234D, User Manual

Page: 141 / 216

AT Commands
Page 141
Modem Configuration
Modem performance will be improved by modification of your standard
configuration; it is recommended that the landline modem also be EC compatible
for reliable communications.
Cell Site AT&F
Base Site AT&F -SEC=1,18
MNP10-EC is automatically enabled on the cell side when a cellular phone driver
is loaded and the modem firmware detects that the cellular phone is attached, also
in the V.34 mode the modem is automatically configured to force the connection in
V.32bis mode.
On the cell side the transmit level is defined in the cellular driver, therefore it is not
necessary to set the level using the AT-SEC command.
In the V.34 mode, on the landline side, if MNP10-EC is disabled (AT-SEC=0), it
will automatically be enabled if another V.34 modem is calling (V.8bis/V.8 signal
indicates cellular capability). No particular modulation will be chosen on the land
line side. Therefore if a landside V.34 modem is NOT going to receive any calls
from a V.32bis MNP10-EC modem it can be configured using AT&F -SEC=0,18
, otherwise use the configuration above.
If MNP10-EC is enabled manually (using AT-SEC=1,) no particular modulation
will be chosen; therefore, 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 initialization 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.