Multitech MT1432BA - Manual (Page 54)

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MultiModemBA User Guide
5.4.4 Configuration and Default Storage Commands
Store Configuration & S-Register Parameters in Non-Volatile Memory &W
The modem can store configuration parameters and S-Register values in its nonvolatile read/write
Random Access Memory (RAM) memory. The &W command does this, which prevents any re-
configuration from being lost on a power-down or Reset (ATZ) condition.
&W0 (or AT&W) causes the modem to store your customized AT command settings and S-Register
values in its nonvolatile RAM. &W0 also sets the modem so that it reads your customized settings
stored in nonvolatile RAM when powered down or reset. (The &W0 command only changes the
settings stored in nonvolatile RAM that you specifically intend to alter. All other default parameters
are applicable.)
&W1 causes the modem not to store your customized settings to nonvolatile RAM so that, after
powering down or resetting the modem, it reads the factory default settings stored in ROM.
Loading Factory Defaults &F
The &F command provides a choice between customized configuration settings in RAM and the
factory default configuration settings in ROM. The &F8 and &F9 commands define the function of the
&F command.
The modem is shipped from the factory with a pre-configured set of command and S-Register default
settings. This set of factory defaults can be recalled by issuing the &F command.
In addition to being able to recall the factory-installed defaults, the &F command can also recall those
defaults stored under &W0.
This is done using the &F9 command. If you have stored parameters with the &W0 command and
wish these settings to always be used as your defaults, you would enter &F9&W0.
To return the &F command to read factory installed defaults, enter &F8&W0. &F8 is the factory
default.
Many datacomm program issue the &F command automatically- the &F9 command allows the user
to select their own factory defaults. Note that the &F8/&F9 commands should be used with &W0.
Following is a summary of how the &F and Z reset commands interact with the &W command; note
how the &F reset command operates differently from the Z reset command:
Previous Command AT&F Power-On and ATZ
AT&W1 (default) ROM ROM
AT&W0 ROM NVRAM
AT&F8&W0 ROM NVRAM
AT&F9&W0 NVRAM NVRAM
Modem Reset Z
The Z command can be used to reset the entire Command Mode buffer and the result is the same as
if you had disconnected, and then reconnected power to the modem. When an ATZ command is
executed, the state of the &W command determines where the default values originate. &W0 defaults
come from RAM and &W1 defaults come from ROM.