Chapter 2 – AT Commands
Multi-Tech Systems, Inc. AT Commands Reference Guide (S000273G) 8
Note: For use with MT5600BA and MT5600BR only.
Values: n = 0 or 1
Default: 0
Description: Y0 Disables sending/resp onding to a long space break signal on disconnect.
Y1 Enables long s pace d isconnect. In non-error correction mode, the modem sends a
long space of four seconds prior to going on-hook. In non-error correction mode,
the modem responds to the receipt of a long space (i.e., a break signal greater than
1.6 seconds) by going on-hook.
Values: n = 0 or 1
Default: None
Description: The modem performs a soft reset and restores (recalls) the configuration profile according
to the parameter supplied. If no parameter is specified, zero is assumed.
Z0 Resets modem and restores Profile 0.
Z1 Resets modem and restores Profile 1.
Note: See also the &F and &W commands.
Values: n = 0 or 1 (all models) 2, 3, 4, 5, 6, 7 (MT5600BA and MT5600BR only)
Default: 1, 3, 4
Description: &C0 Turns off reset on loss of carrier.
&C1 A second way to turn off reset on loss of carrier.
&C2 DCD goes high 500ms after CONNECT message is generated.
&C3 DCD goes high when the CONNECT message is generated.
&C4 Disables &C5 and &C6 commands.
&C5 UNIX only: Holds DCD low until proper callback security pass word is entere d or
until a disconnect occurs. This prevents UNIX login prompt from being displayed
before the callback security ENTER PASSWORD prompt appears.
&C6 Linux only: Waits to display the connect message until the proper callb ack securit y
password is entered.
&C7 Resets on loss of DCD.
Values: n = 0, 1, 2, or3
Default: 2
Description: This command interprets the high to low transition of the DTR signal sent by the computer
according to the supplied parameter. The action taken depends on the current &Q setting.
&D0 &Q0, &Q5,&Q6: DTR is ignored (assumed high). Allows operation with computers
that do not provide DTR.
&Q1: DTR drop causes the modem to hang up. Autoanswer is not affected.
&Q2,&Q3: DTR drop causes the modem to hang up. Autoanswer is inhibited.
&D1 &Q0, &Q1, &Q5,&Q6: DTR drop is interpreted by the modem as if the
asynchronous escape sequence had been entered. The modem returns to
asynchronous command state without disconnecting.
&Q2,&Q3: DTR drop causes the modem to hang up. Autoanswer is inhibited.
&D2 &Q0–&Q6: DTR drop causes the modem to hang up. Autoanswer is inhibited.
&D3 &Q0, &Q1, &Q5,&Q6: DTR drop causes modem to perform a soft reset as if the Z
command were received. The &Y setting determines which profile is loaded.
&Q2,&Q3: DTR drop causes the modem to hang up. Autoanswer is inhibited.
&Q5 or &Q6 and +FCLASS=1 or +FCLASS=2: Same as for &Q0.
Note: If &D1, &D2,or &D3 is set, the modem will not dial without a DTR drop.
Note: For use with MT5600BA and MT5600BR only.
Values: n = 0, 1, or 2
Default: 1
Description: &E0 V.42 non- error correction mode (V.42 disabled).
&E1 V.42 auto-reli able mode.
&E2 V.42 reliabl e mode (V.42 enabled).