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User’s Guide and Reference 4 - 9
Basic Modem Operation
Modem Configurations for Cellular Operation
The Trumpcard’s performance will be improved by modifying the standard
(factory default) configuration. For reliable communications, it is also
recommended that the Modem to which you are connecting also be
MNP10 compatible. Using a MNP10 link will allow negotiation of the
Modem link speeds based on current line conditions.
For a MNP10 to MNP10 link negotiation at 1200 bps the Trumpcard
initialization string would be:
AT&F&C1&D2S95=44)M1*H1:E0
The other Modem, if a landline based Modem, can be initialized with:
AT&F&C1&D2S95=44
In this configuration the modems will first establish a MNP10 link at 1200
bps. They will then make a step up to 4800 bps and then step up to a final
speed based on the line conditions. The total connect time for this method
can be up to 60 seconds.
For a MNP10 to MNP10 link negotiation at 4800 bps (quick connect) the
Trumpcard initialization string would be:
AT&F&C1&D2S95=44)M1*H2:E0.
The other Modem if a landline based Modem can be initialized with
AT&F&C1&D2S95=44)M1@M18
In this configuration the modems will first establish a MNP10 link at 4800
bps and then step up to a final speed based on the line conditions. The
total connect time for this method can be up to 40 seconds.
For connecting to modems that do not support MNP10 the Trumpcard
initialization string would be
AT&F&C1&D2S95=44:E0%E2
which will result in the Trumpcard trying to establish the best possible link
speed. If it is found that connections cannot be reliably made, then it may
be necessary to force the Trumpcard connection to 4800 bps using the
initialization string
AT&F&C1&D2S95=44:E0%E2F6.
Note: Refer to the [n command for details on how to combine cellular and
land based initialization strings.