BASIC AT COMMANDS Command Description AT Attention characters ATA Answer command ATA/ Re-Execute last command Transmit Carrier Signal ATC0 Transmit carrier signal off. (default) ATC1 Transmit carrier signal on. Dial Modifiers Dial Options Description ATD none Dial. (ATD followed by phone number) ATDL none Re-dial. ATDP none Pulse (rotary) dial. 10 pulses per second. ATDT none Touch tone dial (DTMF). ATDW 1-255sec Wait for dial-tone. Default is 50 seconds. ATD, 0-255sec Pause. Default is 2 seconds. ATD@ none Wait for quiet answer. ATD! none Initiate hook flash. ATD; none Return to command state after dialing. ATD^ none Disable calling tone. ATDS=0-3 none Dial stored number. Command Description ATE0 Disables echoing of the commands to the screen. ATE1 Enables echoing of the commands to the screen. (default) ATH0 Instructs modem to go on-hook. ATH1 Instructs modem to go off-hook. ATI0 Displays the product identification code. ATI1 Displays the checksum. ATI2 Displays ROM checksum as OK or ERROR. ATI3 Displays the firmware revision level. Speaker volume ATL0 Off or low volume. ATL1 Low volume. (default) ATL2 Medium volume. ATL3 High volume. Speaker control ATM0 Disables the modem speaker. ATM1 Turns speaker on until carrier has been detected. (default) ATM2 Instructs the modem speaker to stay on all of the time. ATM3 Enables speaker after dialing until connection is established. Automode enable ATN0 Requires speed of the connection be that specified by the value of S37. ATN1 Permits handshaking at any speed supported by both modems. (default) Return to on line state mode ATO0 Switches the modem from command mode to online mode without dialing. ATO1 Switches from command mode to on-line mode and initiates an equalizer retrain sequence during 2400 baud bps operation. Mode responses ATQ0 Enables result codes to be issued to the screen. (default) ATQ1 Disables result codes to be issued to the screen. Result code format ATV0 Numeric format. ATV1 Verbal format. (default) Error correction message control ATW0 Error correction call progress not reported. (default) ATW1 Call progress reported. ATW2 Call progress not reported. Connect xxxx message reports DCE speed. Extended result codes ATX0 Disables monitoring of busy tones unless forced otherwise by country requirements; sends only OK, CONNECT, RING, NO CARRIER, ERROR and NO ANSWER result codes. ATX1 Disables monitoring of busy tones unless forced otherwise by country requirements; sends only OK, CONNECT, RING, NO CARRIER, ERROR, NO ANSWER and CONNECT XXXX result codes. ATX2 Disables monitoring of busy tones unless forced otherwise by country requirements; sends only OK, CONNECT, RING, NO CARRIER, ERROR, DIAL TONE, NO ANSWER and CONNECT XXXX result codes. ATX3 Enables monitoring of busy tones; sends only OK, CONNECT, RING, NO CARRIER, ERROR, NO DIALTONE, NO ANSWER and CONNECT XXXX. ATX4 Enables monitoring of busy tones and sends all messages. (default) Control long space disconnect ATY0 Disables long space disconnect. (default) ATY1 Enables long space connect. Soft reset and restore profile ATZ0 Restores stored profile 0. (default) ATZ1 Restores stored profile 1. +++ Escape characters. The escape characters are known as +++. They will switch from on-line mode to command mode while preserving the connection with the online modem. Extended AT Commands Command Description Data carrier detect (DCD) signal AT&C0 Forces DCD signal to be on at all times. (default) AT&C1 DCD on indicates presence of data carrier. Data terminal ready (DTR) signal. Interprets the ON to OFF transition of the DTR signal from the DTE according to the &Q settings. AT&D0 &Q0,5,6. DTR ignored. &Q1,4. Modem hangs up; auto answer not affected. &Q2,3. Modem hangs up; auto answer inhibited. (default) AT&D1 &Q0,1,4-6. Asynchronous escape sequence. &Q2,3. Modem hangs up; auto answer inhibited. AT&D2 &Q0-6. Modem hangs up; auto answer inhibited. AT&D3 &Q0,1,4-6. Modem does a soft reset as if the ATZ command were received; &Q2,3. Modem hangs up; auto answer inhibited. AT&F Recalls factory defaults. Instructs the modem to use the factory set parameters. DTE/Modem flow control AT&K0 Disable flow control. AT&K3 Enable RTS/CTS (default for data modem) AT&K4 Enable XON/XOFF. AT&K5 Enable transport XON/XOFF. AT&K6 Enable both RTS/CTS and XON/XOFF (default for FAX modem) Note on Flow Control. XON/XOFF is a software-based flow control method, using standard ASCII control characters to pause or resume data transmission.RTS/CTS pacing, a hardware-based method, uses an electrical signal. Signals are exchanged as follows: RECEIVER TRANSMITTER CTS ON ------------> START SENDING CTS ON <----------- RTS ON (ready to send) CTS OFF ------------> RTS OFF (stop sending) Command Description Select pulse dial make/break ratio AT&P0 Selects a make/break ratio of 39/61 at 10pps. US and Canada. (default) AT&P1 Selects a make/break ratio of 33/67 at 10pps. UK and Hong Kong. AT&P2 Same as 0 except at 20pps. AT&P3 Same as 1 except at 20pps. Asynchronous mode AT&Q0 Direct Asynchronous mode. AT&Q5 Modem negotiates an error-corrected link. (default) AT&Q6 Selects asynchronous operation in normal mode (i.e. speed buffering). Data Set Ready (DSR) signal AT&S0 Causes DSR signal to be active at all times. (default) AT&S1 Causes DSR signal to be active according to the CCITT specification. Test and diagnostics AT&T0 Terminates any test in progress. AT&T1 Executes the local analog loopback test. AT&T3 Executes the local digital loopback test. AT&T4 Enables the modem to accept a request from a remote mode for a digital loopback test. (default) AT&T5 Instructs the modem to deny a request from a remote modem for a digital loopback test. AT&T6 Executes the remote digital loopback test. AT&T7 Executes the remote digital loopback test with a self test. AT&T8 Executes the remote analog loopback test with a self test. AT&V View current configuration and user profile. Store user profile. Saves the current configuration into non-volatile RAM as one of two user profiles. AT&W0 Saves as user profile 0. AT&W1 Saves as user profile 1. Designate default user profile AT&Y0 Selects user profile 0. AT&Y1 Selects user profile 1. Stored phone number AT&Z=0 Stores a 36 digit dial string. AT&Z=1 Stores a 36 digit dial string. AT&Z=2 Stores a 36 digit dial string. AT&Z=3 Stores a 36 digit dial string. MNP Operation The V.FAST Class Modem supports all of the preceding classes. The following AT Commands apply to the MNP protocol: Maximum MNP Block Size. Use this command to transmit smaller blocks of data in a reliable data link connection. AT\A0 set maximum block size to 64 characters. AT\A1 set maximum block size to 128 characters. (default) AT\A2 set maximum block size to 192 characters. AT\A3 set maximum block size to 256 characters. Transmit Break. When this command is entered during a non-MNP connection, a break signal is sent to the remote modem. The length of the break is 100 times the n parameter (1-9) in milliseconds. The default is 3. AT\B3 (default) Modem to Modem Flow Control. Enables or disables modem to modem flow control during a normal mode connection. This command is ignored when error correction is selected. AT\G0 Disables flow control (XON/XOFF) (default) AT\G1 Enables flow control (XON/XOFF) Break Control. Determines the modem response when a BREAK is received from the DTE or the remote modem. The values of the parameters vary based on the three following conditions: (1) When a break is received from the DTE during NORMAL or MNP mode: AT\K0, 2, 4 modem enters command mode without sending a break to the remote modem. AT\K1 modem clears the terminal and modem buffers and sends a break to the remote modem. AT\K3 modem does not clear the buffers, but sends a break to the remote modem. AT\K5 modem sends a break to the remote modem in sequence with any transmitted data. (default) (2) When a break is received from the remote modem during NORMAL mode: AT\K0, 1 modem clears the terminal and modem buffers and sends a break to the local DTE. AT\K2, 3 modem does not clear the buffers but sends a break to the local DTE. AT\K4, 5 modem sends a break in sequence with any data being buffered. (default) (3) When a break is received from the DTE during DIRECT MODE mode: AT\K0,1,3 modem sends a break to the remote modem and enters command mode. AT\K2, 4, 5 modem sends a break to the remote modem. (default) MNP Block Transfer Control. Determines whether or not the modem will use block or stream mode for MNP link. AT\L0 uses stream mode for MNP link connections (default) AT\L1 uses block mode for MNP connections Error Correction Operating Mode. Selects the operating mode the modem uses while connected. AT\N0 NORMAL (speed buffering) mode. AT\N1 DIRECT (pass-through) mode. AT\N2 RELIABLE LINK mode. Specifies error correction for the modem-to-modem connection AT\N3 AUTO-RELIABLE LINK mode. Attempts error-correction connection but will fall back to normal mode if unable to establish an MNP link. AT\N4 LAPM error correction mode. AT\N5 MNP error correction mode Split Speed Operation. Supports a split-speed DCE/DTE interface for applications which require a transmit speed of 75bps and receive speed of 1200bps at the DTE interface. AT\W0 disables (default) AT\W1 enables MNP Link Negotiation Speed. Controls the connection speed for link negotiations. AT*H0 link negotiation occurs at the highest supported speed. (default) AT*H1 link negotiation occurs at 1200bps. S-Registers This section defines the purpose of the modem registers, and sequentially lists the registers and describes their functions. These registers affect various operating characteristics and allow you to obtain information about the modem, as well as test the modem. Each register has a factory-set value, which you can read or change to fit your needs. Reading a Register Value To read the current value of a register, type: AT Sn? [ENTER], where n is a register number. AT Sn? Sn? [ENTER] from the command mode. To read the register values of S0 and S1, type AT S0? S1? [ENTER]. The modem will display the first register value, a carriage return, the next register value, a carriage return, and OK or 0. Changing a Register Value To change a register value, use the Sn command (ATSn=v), where n is a register number and v is the new value you want to assign to the register. Type: AT S0=3 [ENTER] to have the modem automatically answer on the third ring. The following table lists the modem's registers and their functions: Reg. Range Units Default Definition S0 0-255 rings 2 Auto-answer S1 0-255 rings 0 Count incoming rings S2 0-255 rings 43 Escape character value. S3 0-127 ASCII 13 Carriage return character. S4 0-127 ASCII 10 Line feed character. S5 0-32 ASCII 8 Backspace character. S6 2-255 seconds 2 Wait time for Blind Dialing. S7 1-255 seconds 50 Wait for carrier after dial. S8 0-255 seconds 2 Pause time for dial delay. S9 1-255 seconds 6/10 Carrier detect. S10 1-255 seconds 14 (1.4) Lost Carrier to Hang Up Delay. S11 Reserved. S12 0-255 seconds 50(1) Escape code guard time*. (*in one-fiftieth second increments) S13 Reserved. S14 Bit Mapped AA,hex Bit mapped registers. S15 Reserved S16 Bit Mapped 80,hex Modem test options. S17 Reserved. S18 0-255 seconds 0 Test timer. S19 Reserved. S20 Reserved. S21 Bit Mapped 00,hex Bit mapped registers. S22 Bit Mapped 75,hex Bit mapped registers. S23 Bit Mapped 07,hex Bit mapped registers. S24 0-255 seconds 0 Sleep Inactivity Timer. S25 0-255 seconds 5 Asynchronous DTR Delay. S26 0-255 seconds 1 Delay Interval. S27 Bit Mapped 9,hex Bit mapped registers. S28 Bit Mapped Bit mapped registers S29 Reserved. S30 0-255 seconds 0 Inactivity Timer. S31 Bit Mapped Options. S32 0-255 ASCII 17 XON Character. S33 0-255 ASCII 19 XOFF Character. S34-35 Reserved. S36 Bit Mapped Options. S37 0-12 0 Telephone Line Speed NOTE: This is interlinked with the ATFn command. If an invalid number is entered, the number is accepted into the register, but S37 will react as though the default value has been entered. Bits 0-3 0 = Attempt auto mode connection (ATF0)(DEFAULT) 1-3 = Attempt to connect at 300bps 4 = Reserved 5 = Attempt to connect at 1200bps (ATF1) 6 = Attempt to connect at 2400bps (ATF4) 7 = Attempt to connect at V.23 (ATF3) 8 = Attempt to connect at 4800bps (ATF6) 9 = Attempt to connect at 9600bps (ATF8) 10 = Attempt to connect at 12Kbps (ATF9) 11 = Attempt to connect at 14.4Kbps (ATF10) 12 = Attempt to connect at 7200bps (ATF7) Bits 4-7 Reserved S38 0-255 seconds 20 Delay Before Forced Hangup. S39 Bit Mapped Bit Mapped Registers. S40 Bit Mapped Bit Mapped Registers. S41 Bit Mapped Bit Mapped Registers. S42-45 Reserved. S46 136 or 138 138 Data Compression Control. NOTE: 136 enables error correction with no compression; 138 enables error correction WITH compression. S48 0, 7, 128 7 V.42 Negotiation. NOTE: 0 disables negotiation and proceeds with LAPM; 7 enables negotiation; and 128 disables negotiation and proceeds with fallback action specified in S36. The default for S36 is to attempt an MNP connection. S49-81 Reserved. S82 3, 7, 128 128 Break Handling Option. S86 N/A Connection Failure Cause Code. S91 0 to -15 dBm 10 PSTN Transmit Level. S92 0 to -15 dBm 10 Fax Transmit Level. S95 Bit-Mapped NA Extended Results Codes. NOTE: Bit values are defined as follows for S95: 0 = CONNECT CODE indicates DCE speed instead of DTE speed. 1 = Append ARQ (automatic repeat request) to verbose CONNECT XXXX result code if protocol is other than none. 2 = Enable CARRIER XXXX result code. 3 = Enable PROTOCOL XXXX result code. 5 = Enable COMPRESSION result code. Bits 4, 6, and 7 are reserved. Result Codes Result Numeric Code Value Description OK 0 Modem successfully executed a command line. CONNECT 1 Connection made at 300 bps. RING 2 Modem detected an incoming call. NO CARRIER 3 Modem lost or could not detect a remote carrier signal within the Register S7 time. ERROR 4 Modem found an error in the command line. CONNECT 5 Modem established a connection 1200 at 1200 1200bps. NO 6 Modem did not detect a dial tone within 5 DIALTONE seconds after going off-hook. BUSY 7 Modem detected a busy signal. NO ANSWER 8 Five seconds of silence was not detected when using the @ command in the dial command line. CONNECT 0600 9 Modem established a connection at 600 bps. CONNECT 2400 10 Modem established a connection at 2400 bps. CONNECT 4800 11 Modem established a connection at 4800 bps. CONNECT 9600 12 Connection made at 9600 bps. +FCERROR +F4 Fax carrier error. CONNECT 7200 13 Connected as data modem during an 7200 answer. CONNECT 12000 14 Connection made at 12000 bps. CONNECT 14400 15 Connection made at 14400 bps. CONNECT 19200 16 Connection made at 19200 bps. CONNECT 38400 17 Connection made at 38400 bps. CONNECT 57600 18 Connection made at 57600 bps. CONNECT 22 Modem returns this result code when upon 75TX/1200RX establishing a V.23 originate connection when the modem has been instructed to report the DTE speed to the DTE upon connecting. CONNECT 23 Modem returns this result code when upon 1200RX/75RX establishing a V.23 answer connection when the modem has been instructed to report the DTE speed to the DTE upon connecting. CARRIER 300 40 Carrier rate of 300 bps. CARRIER 44 V.23 backward channel has been detected. 1200/75 CARRIER 45 V.23 forward channel has been detected 75/1200 CARRIER 1200 46 Carrier rate of 1200 bps. CARRIER 2400 47 Carrier rate of 2400 bps. CARRIER 4800 48 Carrier rate of 4800 bps. CARRIER 7200 49 Carrier rate of 7200 bps. CARRIER 9600 50 Carrier rate of 9600 bps. CARRIER 12000 51 Carrier rate of 12000 bps. CARRIER 14400 52 Carrier rate of 14400 bps. COMPRESSION: 66 The modem has connected in MNP class 5 CLASS 5 and COMPRESSION message reporting has been enabled. COMPRESSION 67 The modem has connected in V.42bis and V.42bis COMPRESSION message reporting has been enabled. COMPRESSION: 69 The modem has connected without data NONE compression and COMPRESSION message reporting has been enabled. PROTOCOL: 76 Modem has connected without any form of error NONE* correction. PROTOCOL: 77 Modem has connected in the V.42 LAPM mode LAPM* LAPM mode of error correction. PROTOCOL: 80 Modem has connected in the MNP mode of error ALT* correction. PROTOCOL: 81 Modem has connected in the MNP10 mode ALT* CELLULAR * PROTOCOL message reporting has been enabled.