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AT&D Controlling Data Terminal Ready
The DTR signal is used to indicate to the modem whether your computer is ready to
communicate.
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The &D command will only take effect when the DTR option switch is in the UP
position and %S0 is selected. (See the Dumb Mode Section for details.)
Options
AT&D0 The modem ignores the DTR signal and acts as if it is asserted (the modem
assumes the computer is ready to communicate).
AT&D1 The modem will return to on line command state if DTR is lowered during a
connection.
AT&D2 ■ The modem will hang up, return to local command state and disable auto-
answer whilst DTR is low (is not asserted).
To enable auto-answer, the DTR signal must be asserted.
The computer must assert DTR before dialling or answering may commence.
AT&D3 If DTR is lowered, the modem will hang up, return to local command state
and initialise itself with the values stored in the &Y profile.
AT&D4 The modem will hang up, return to local command state and go off-hook. It
will remain off-hook whilst DTR is low.
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S Register 25 determines how long DTR must be low before the modem recognises
it as such.
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S Register 57 determines how long DTR must be high before the modem
recognises it as such.
Range
0-4
See Also
S 25, S 57 DTR Detection Times