User's Manual

&D – DTR (Data Terminal Ready) Option
This command controls how the modem responds to DTR. After toggling DTR,
the host should wait 200 ms before modifying the UART registers or sending a
new command to the modem. This is done because the modem does not send
an ’OK’ message to indicate it has performed the requested function.
AT&D0 In asynchronous mode (&Q0), the modem ignores DTR.
AT&D1 The modem switches from data mode to command mode when
an on-to-off transition of DTR occurs.
AT&D2 An on-to-off transition of DTR causes the modem to go on-hook
(hang-up). While DTR is off, auto-answer is disabled.
AT&D3 An on-to-off transition of DTR re-initializes the modem. The re-
initialize procedure performs the same function as a power-up
reset, except that the UART registers are not reconfigured.
&F – Loading the Factory Settings
This command loads command defaults and S-Register factory defaults into
the active configuration and configures the modem for data mode.
A Selection of &F0 Factory Settings
E1 Echo enabled
L2 Middle speaker volume
M1 Speaker on until carrier present
Q0 Result codes enabled
V1 Verbose (text) form
Y0 Disables long space disconnect
X4 Result codes 0-5, 7, 10 and above enabled. Busy detect enabled
and dial tone detect diaabled
&C1 State of carrier from remote modem is tracked. DCD reflects the
state of the received carrier.
&G0 Guard tone disabled
&R1 RS always On
&T5 Denies RDL request from remote modem
S0=0 No automatic answer
\N3 V.42 - Auto-Reliable Mode
=> (Further settings are covered by the descriptions of the individual
Commands and Registers).
2-10 AT COMMANDS: DATA MODEM