Synxcom SM9234D, User Manual

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Using the Modem’s Auto-Connect Feature
Page 29
Chapter 4
Using the Modem’s Auto-Connect
Feature
Your SM9256D modem can emulate a leased-line connection over the Public Switched
Telephone Network (PSTN). Using the $DL command, you can configure the modem to work
similarly to the “always connected” functionality used with leased lines. This feature is useful in
environments where a leased line is not available or is cost prohibitive. In certain environments,
this feature is more robust in recovering from network failures.
When the $DL command is used, your SM9256D modem automatically dials the first of four
telephone numbers you have stored using the &Zn=x command. If the call fails or is
disconnected, your modem waits a user-defined number of seconds before redialing the number. If
the redialing attempt fails to make a connection (for example, if the number dialed is busy or the
called modem does not answer), your modem automatically dials the next number stored with the
&Zn=x command. The modem repeats this round-robin method until a dialed number results in a
data connection.
Storing Telephone Numbers
Before you use the &Zn=x command, store up to four telephone numbers in your modem’s
nonvolatile memory. These are the telephone numbers your modem automatically dials when it
executes an $DL command.
In the command &Zn=x, n is a decimal number from 0 to 3 that corresponds to a location in the
modem’s nonvolatile memory and x is a dial string up to 31 characters long. The following
examples show how to store sample dial strings in the modem’s nonvolatile memory.
Example Description
AT&Z0=5551212 Stores dial string 5551212 in nonvolatile memory location 0.
AT&Z1=9,19495551234 Stores dial string 9,19495551234 in nonvolatile memory location 1.
AT&Z2=T9,P5552468 Stores dial string AT&Z2=T9,P5552468 in nonvolatile memory
location 2.