VT-MODEM User Manual
Page 18 of 30
Last Revised: 17-Aug-09
Sixnet Technology Park
331 Ushers Road
Clifton Park, NY 12065 USA
+1 (518) 877-5173
support@sixnet.com
Section 6
AT Command Summary
All VT-MODEM models support the AT commands, Fax Class 1 and Class 2 commands listed in this
Section. The VT-MODEM contains a set of factory default settings, which can always be restored by the
user. (See the &F command.) The modem also provides two user profiles (profile 0 and profile 1) which
hold settings as set and saved by the user. (See the &W command.) The settings currently in use by the
modem are generally referred to as the active configuration.
Notes:
VT-MODEM-2 self-dial parameters and VT-MODEM-3 RS422 / RS485 port parameters can only be set using the VT-
MODEM SETUP Wizard, which is provided on the Sixnet Programmable I/O for Windows CD. Refer to the on-line
help in the VT-MODEM Setup Wizard for more information.
The following tables only list the AT commands supported by the current modem firmware. For a complete
list of AT commands, all valid parameters, and default settings for each AT command please see the Sixnet
online help system of the VT-MODEM Setup Wizard.
Commands marked with an asterisk (*) have different characteristics, depending on the revision of VT-
MODEM being used. Refer to the online help system of the VT-MODEM Setup Wizard for the details of
these differences.
Command Function
A/
Re-execute Last Command; do not precede with AT command and do not follow with a carriage
return.
A
Go off hook and Answer A Call
AT=x
Write value x to last selected register.
AT?
Report the value of last selected register.
Bn
Set data standard to CCITT(Europe et. al.) or Bell Mode(U.S., Canada) for connections at 300 or
1200 bps.
Cn
Carrier Control (parameter = 1 only)
Dn
Dial (originate a call); typical usage: ATDT5551212 to tone dial number. ATDS=n to dial nth
stored number.
E
Echo command to monitor when typed
Fn Not
available.
Hn
Disconnect (Hang up)
In
Identification; reports product code, name, ROM and firmware data, etc.
Ln
Speaker Volume (not available)
Mn
Speaker Control (not available)
*
Nn
Automode Enable; enabled allows connection at highest possible modem speed, disabled fixes
speed according to register S37.
On
Return To On-line Data Mode
P
Set Pulse Dial Default.
Qn
Quiet Results Codes Control; when enabled, result codes are reported to the monitor.
Sn
Establishes S Register n as the last register accessed
Sn-x
Write value x to S Register n.
Sn?
Reports the value of S Register n.
T
Set Tone Dial Default
Vn
Set Result Code Format to terse or verbose.
Wn
Connect Message Control sets the format of the connect messages.
Xn
Extended results code
Yn
Long space disconnect
Zn
Perform Soft Reset and Restore stored user configuration profile 0 or 1.
&Cn
RLSD (DCD) Option; set DCD signal to indicate presence of carrier or forces DCD signal on at
all times.
&Dn
DTR Option; set how modem interprets the DTR signal.
