Coastcom D/I Mux III System User Manual page 315

D/I Mux III User's Manual Appendix I. Traps and Modem Dial Out Configuration
ANALYSIS OF DEFAULT INITIALIZATION STRING
Note: This is a breakdown analysis of the default initialization string.
ATZV1&D2&C1E0
AT is the attention prefix—this precedes all commands except for escape sequence or the repeat
command.
Z means reset the modem and recall the factory configuration.
V1 displays the result code(s) in the form of words.
&D2 assume the command state when an on-to-off transition of DTR occurs.
&C1 Track the presence of a data carrier.
Use &D2&C1 because software convention assumes that when DTR goes low the modem will hang up.
Using the factory default &D0&C0 will not hang up when DTR goes low.
E0 Disable character echo in command state.
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