&Dn - Select Data Terminal Ready Option


Command Line Format
AT [cmds] &D [suffix] [cmds] <CR>

Suffix Values
0 through 3

Default
&D0

Stored by &Wn
yes

Displayed by &V
yes

Description
The &Dn command controls how the modem responds to the state of DTR and changes of DTR. The effects of DTR states and changes are also dependent upon the current communication mode (&Qn or &Mn command). The test modes associated with certain &Tn commands are only affected by DTR changes when &D3 is in effect and are not affected by &Qn or &Mn commands.

The TR LED shows the state of DTR except when &D0 and &Q0 are in effect. Note that TR may have special uses in certain test modes.

Select one of the following topics for a description of what DTR does for each mode of modem operation.

Dumb, switched

Smart AT, switched

Dumb Leased Line

Timing of DTR Off-To-On Transitions

Timing of DTR On-To-Off Transitions

DTR-Initiated Hard Reset (&D3 in effect)

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