AT Commands

Links to other Reference Manual pages

[Reference Manual Table of Contents]
[Using AT Commands and Result Codes]
[Factory Defaults and Active Configurations]

[Dialing and Answering]
[Result Codes]
[S Register Descriptions]

This appendix describes your modem's data mode commands. Each of these commands should be preceded by AT, except for the A/, AT command, and Escape Code.

+++ Escape Code
A Answer Phone Line
A/ Re-execute Last Command: Re-execute the last command issued. The last command might have been issued by you or by your software.
AT ``ATtention'' Command Line Prefix
B BELL/ITU-TSS Protocol Compatibility: B Selects ITU-TSS protocols at 300 or 1200 bps (international standard); B1 Selects Bell protocols at 300 or 1200 bps (US standard)
Dn Dial Telephone Number
E Command Echo: Controls the echo of characters sent to your modem from your computer when the modem is in the command state.; E Inhibit command echo. If you see two characters for every one you type (i.e. AT looks like AATT), issue E.; E1 Enable command echo (default). If your computer does not display the characters you type, issue E1.
H Hook Control: H On-hook (hang up).; H1 Off-hook (pick up phone line).
I Report Identification and Diagnostic Information: I6 Report current country code setting.; I7 Report data pump model.; I10 Report optional features supported by your modem.
L Speaker Volume: L=low, L2=medium (default), L3=high.
M Speaker Control: M Always off.; M1 On until carrier is received (default).; M2 Always on.; M3 Off while dialing and after carrier is received; on when answering.
O Going Online: O Go online (after using +++).; O1 Go online; initiate retrain sequence.
Q Enable/Disable Result Codes: Q Result codes enabled (default).; Q1 Result codes disabled.
Sr? Read S Registers: Return the value in S register r.; Write value n to S register r.
W Error Correction Result Codes: W Result codes not reported and CONNECT XXXX reports computer (DTE) rate (default).; W1 Reports Error correction mode.; W2 Result codes not reported and CONNECT XXXX reports connection (DCE) rate.
X Dialing Type and CONNECT Result Codes: X Blind dial (ignore dial tone and busy signal) and send CONNECT when connected.; X1 Blind dial; send CONNECT XXXX result codes when connected.; X2 Wait for dial tone before dialing; send CONNECT XXXX result codes; do not detect busy signal.; X3 Ignore dial tone; send CONNECT XXXX result codes; send BUSY if busy signal detected.; X4 Send codes set by Wn and S95 when connected. Send BUSY code if busy signal detected; send NO DIALTONE code if dial tone is not received (default).
&C Data-Carrier-Detect (DCD) Signal Control: Determines DCD behavior. Default depends on &F setting.; &C DCD signal always on.; &C1 DCD indicates when carrier from remote modem is present.
&D Select Modem Reaction to DTR: Sets how your modem reacts to an on-to-off transition of DTR.; &D Ignore an on-to-off transition of DTR.; &D1 Switch to asynchronous command state.; &D2 Disconnect and return to command state. Auto answer mode disabled while DTR is off.; &D3 Perform soft reset.
&F Load Factory Default Configuration: &F Restore factory default configuration (default for PCs). Includes hardware flow control, error correction and data compression.; &F1 Restore factory default configuration (default for Macs).
#VLS=x Voice Line Select: x=0: Telephone Handset (Default); x=6: Speakerphone; NOTE: Before you issue this command, your modem must be in voice mode; this can be done with the command AT#CLS=8. Also, the #VLS command must be issued prior to establishing an SVD connection if a voice line other than the default telephone handset is desired.
#CLS=x Select Data, Fax or Voice/Audio: This command selects data, fax or voice/audio mode from operation in any mode.; x=0: Data mode; instructs the modem to act like a data modem for subsequent answer or originate operations.; x=1: Class 1 fax; x=8: Voice/audio mode; used to set the modem for answer or originate sequences that involve voice modes.; NOTE: This command must be used before you select a voice line mode using #VLS.
+V Show Configuration Profile: Display active configuration.
+MS Select Modulation: You can control the modulation your modem uses to negotiate a connection by entering the +MS command. This command allows you to select a specific modulation, enable or disable automode, and specify the highest and lowest connection rates for your modem. You use a variation of the +MS command to report selected options and supported options.; The command format for AT+MS is:; AT+MS = <mod>,<automode>,<minimum rate>,<maximum rate>,<codec>,<rbsignaling>,<max upload speed> [CR]; You can leave a parameter at its current value by leaving that parameter's place blank and entering a comma to separate the parameters or by entering a carriage return ([CR]) if it is the last parameter.; To specify a preferred modulation, enter a character designation from the <mod> column of the following table. The Mod parameter defined:; The <automode> (automatic modulation negotiation) parameter is an optional numeric value that enables or disables automatic modulation negotiation using V.8 or V.32bis Annex A.; The automode parameter defined:; If you set <automode> to 1, your modem attempts to connect at the highest possible rate available through either V.8 or V.32bis Annex A. If your modem cannot make a connection at that speed, it automatically negotiates the rate downward until a connection is made.; If you set <automode> to zero, your modem tries to connect at the highest speed available for the modulation you have selected and will not negotiate if a connection cannot be made.; The <minimum rate> is an optional number that specifies the lowest rate at which the modem may establish a connection. The default is 300 bps.; The <maximum rate> is an optional number that specifies the highest rate at which the modem may establish a connection. The default is 33,600 bps.; The codec parameter defined:; The A-law codec is used in Europe, so the default value should be used there.; The <rbsignaling> parameter stands for "robbed-bit signaling" and is not used in Europe; it should be set to its default value of zero there.; The <max upload speed> is an optional number that specifies the highest rate at which the modem may upload data. The default is 33,600 bps.; You can use AT+MS=? to display the options supported by your modem. The modem displays a list of the selected options in the following format:; list of <mod>values; supported <automode> values; supported <minimum rate> values; supported <maximum rate> values; supported <codec> values; supported <rbsignaling> values; supported <max upload speed> values
\N Operating Mode: \N Normal mode, with flow control.; \N1 Direct mode, without flow control.; \N2 MNP Reliable Mode.; \N3 AutoReliable Mode (default).; \N4 LAPM/MNP Reliable Mode.; \N5 MNP Mode.
%C Enable/Disable Data Compression: %C Data compression disabled.; %C1 MNP 5 enabled.; %C2 V.42bis enabled.; %C3 V.42bis and MNP 5 enabled (default).

[Advanced AT commands for SupraExpress 56 i PRO series]

<mod>	Modulation	Possible Rates (bps)¹	Notes
0	V.21	300
1	V.22	1200
2	V.22bis	2400 or 1200
3	V.23	1200²
9	V.32	9600 or 4800
10	V.32bis	14400, 12000, 9600, 7200, or 4800
11	V.34	33600, 31200, 28800, 26400, 24000, 19200, 16800, 14400, 12000, 9600, 7200, 4800, or 2400	Default
64	Bell 103	300
69	Bell 212	1200
56	K56flex	56000, 54000, 52000, 50000, 58000, 46000, 44000, 42000, 40000, 38000, 36000, 34000, 32000
¹See optional <automode>, <minimum rate>, and <maximum rate> parameters. ²For V.23, originating modes transmit at 75 bps and receive at 1200 bps; answering modes transmit at 1200 bps and receive at 75 bps. The rate is always specified as 1200 bps.

<automode>	Option Selected	Notes
0	Automode disabled
1	Automode enabled using V.8 or V.32bis Annex A	Default