Apple Express Modem AT Commands From Apple Computer’s “Express Modem AT Commands” document on the Express Modem 1.0.4 disk. Converted to DisplayDA by David Good. Note: “Default” settings are in Bold for easy reference. Moving between command and on-line states When the modem is turned on or after reset, the modem always goes to command state. It enters on-line state after successfully making a connection with a remote modem, either when answering or originating a call. While the modem is in on-line state, you can take control of it again (go back to command state). When you return to command state from on-line state, the modem goes to local command state, which allows you to maintain the connection and enter commands.   To go to local command state, type the escape sequence +++.   Do not type any other commands or make entries before or after   the escape sequence for a period equal to the guard time set in   register S12 (normally one second). The modem will display OK.   To go back to on-line state, type ATO.   To hang up, type ATH. AT command set    AT refers to the command prefix (attention sequence) that    precedes each command to the modem. With the exception of A/    all commands must be preceded by AT and end with a carriage    return ().  Special Commands A/  Repeat last command     The A/ command instructs the modem to repeat the last     command line. A command line termination character     is not required for the execution of this command (that is,     the command is executed as soon as the slash is typed). +++ Return to command state (escape sequence)     The escape sequence is used to force the modem back to local     command state from on-line state. Do not type any other     commands or make entries before or after the escape sequence     for a period equal to the guard time set in register S12 (default is one second).  Standard AT commands AT  The attention command prefix     The prefix AT must precede every command. The remainder     of the command line contains commands for the modem. The     command line must end with a carriage return. If AT is sent     alone (that is, it is followed by a ) then no command is     executed but an OK result code is returned. A   Answer     The A command forces the modem to go off-hook in answer     mode. Bn  Communication protocol category preference     This command determines which communication standard is     preferred for the next connection.   0 CCITT mode   1 Bell 103 and Bell 212A, instead of V.21 and V.22, in case of     fallback (default) D   Dial     This command signals the modem that the numbers, letters, and     commas that follow are all part of a telephone number that it     should dial.   T Touch-Tone dialing     This causes all following numbers to be Touch-Tone dialed     (default).   P Pulse dialing     Selects pulse dialing, with the dialing speed fixed at 10 pulses     per second.   Pause     The comma (,) modifier introduces a delay time before dialing     the next dial character or executing the next character in the     dial string. The pause time is the value of the S8 register,     (default=2 seconds).   W Dial tone detect     The W modifier makes the modem detect a dial tone before     sending the next digit.   Calling Card tone detect (:)     Same as W. The colon can detect most calling card tones.     Place the colon in the dial string when you want to detect a     wider range of frequencies.   @ Wait for quiet answer before dialing     For the time specified in the S7 register (default=50 seconds),     the modem attempts to detect 5 seconds of silence.   Flash     The exclamation point (!) causes the modem to go on-hook then     back off-hook, as if the receiver on the telephone set had been     pressed momentarily.   R Reverse mode     The R modifier changes the modem from originate mode to     answer mode after the dialing process is complete. This     command is used only at the end of the dial string.   S=n     Dial telephone number stored at location n     Dials telephone number stored in location n, where n is     0, 1,or 2. You must have previously saved the value with     the AT&Z command. En  Echo off/on     When the echo is turned on, the characters sent to the modem     in command state are echoed back by the modem to the host     computer. The E command is functional only when the modem     is in command state.   0 Turns off the echo command.   1 Turns on the echo command. This allows you to see that     characters you have sent to the modem have been received     and sent back. (default) Hn  Hook (hang up)     When the modem is on-line, you must first enter the +++ escape     sequence to take the modem back to command state before     issuing the hang up command, ATH.   0 Forces the modem on-hook. Hangs up the modem’s connection to     the telephone line.   1 Forces the modem off-hook. In  Information   0 Asks the modem for its product ID code.   1 Returns a modem code.   2 Returns OK.   3 Returns the modem’s country code.   4 Returns a list of modem features.   9 Returns Apple product code and firmware version of the modem. Ln  Speaker volume     This command has no effect as the speaker is a component     of the Macintosh and set in the Sound control panel. The     command is included for compatibility. Mn  Speaker on/off/auto   0 Disables speaker.   1 Turns on the speaker until carrier is established. (default)   2 Leaves the speaker on throughout the entire connection.   3 Turns the speaker on until a carrier is detected, except during     dialing. Nn  Communication protocol preference     Sets the modem protocol.   0 Use S37 for speed selection. If S37=0, connect at highest     possible speed. Otherwise, connect at speed specified in S37.     (default)   1 Connect at highest possible speed. Ignore S37. Fallback if     necessary.   2 Same as N1 for compatibility reasons.        Note: For N1 or S37=0, the setting of ATB is ignored.        The modem automatically determines Bell or CCITT mode. On  Return to on-line state     Returns modem to on-line state from command state.   0 Is used to return to the on-line state after having entered the     command state using the escape sequence.   1 Same as above and will retrain the carrier (possibly at a lower     speed) before reentering on-line state. P   Enable pulse dialing     Sets the default dialing mode to pulse mode. This command     can also be used as a subcommand of the D command. Qn  Quiet (refer to command Vn)   0 Allows result codes to be sent to your screen. (default)   1 Turns off the result code messages.   2 Returns result codes when originating a call, but not when     answering. Sn  Select an S register     The S registers refer to memory locations used for     configuration. The S commands are used to assign values     to various registers in the modem’s memory.  n? The Sn? command (n=register number) is used for checking the     contents of a register. The result is always expressed as a     three-digit number, where the leading digits or all digits may     be 0.  Sn=r is used to change an S register value (where n is the number     of the register and r is the assigned value). S registers       Default      Range       Units S0   Number of rings to auto answer       0           0:255       Number of rings S1   Ring counter       0           0:255       Number of rings S2   Escape Character       43 <+>       0:127       ASCII Decimal S3   Line-termination character       13       0:127       ASCII Decimal S4   Line-feed character       10       0:127       ASCII Decimal S5   Backspace character       8        0:127       ASCII Decimal S6   Initial blind dialing wait       2           2:255       Seconds S7  Carrier wait       50          1:255       Seconds S8   Pause time       2          0:255       Seconds S9   Carrier detect response time       6          1:255       1/10 second S10  Disconnect timing       14         1:255       1/10 second S11  Duration and spacing for DTMFdialing       95         50:255      Milliseconds      Register S11 is preset and should remain unchanged to      assure correct dialing. S12  Escape code guard time       50         20:255      1/50 second S18  Self-test duration       0          0:255       Seconds S36  Negotiation failure treatment       5         0/3/4/5      Settings      Specifies action that should be taken when an attempt to      connect in error-control mode fails.   0  Attempts V.42 connection. Hangs up if remote modem doesn’t      support V.42.   3  Makes asynchronous connection. No error control. Same as      AT&Q0.   4  Attempts V.42 connection. If attempt fails, attempts MNP      2–4 connection. If attempt fails, then hangs up.   5  Attempts V.42 connection. If attempt fails, attempts MNP      2–4 connection. If attempt fails, then attempts      asynchronous connection. (default) S37  Desired DCE connection speed       0          0/3:11       Settings      This value is used in conjunction with the ATN and ATB      values to determine which modulations are attempted when      connecting.   0  Auto-mode Attempts to connect at the highest possible      speed. (default)   3  Attempts to connect at 300 bps.   5  Attempts to connect at 1200 bps.   6  Attempts to connect at 2400 bps.   7  Attempts to connect at 4800 bps.   8  Attempts to connect at 7200 bps.   9  Attempts to connect at 9600 bps.   10 Attempts to connect at 12000 bps.   11 Attempts to connect at 14400 bps. S38  Delay before hang up.       0          0:254       Seconds S46  V.42 bis data compression selection       138        136/138    Settings  136  V.42 only  138  V.42 with V.42 bis compression. (default) S48  Feature negotiation action       7          0/3/7/128   Settings      Selects which error control features are allowed when      making connections.   0  Negotiation disabled: try only V.42.   3  Negotiation enabled without detection phase.   7  Negotiation enabled with detection phase. (default)  128 Negotiation disabled: try MNP only. V.42 disabled. S95  Error control negotiation message option       32         4/8/32       Bits      A bit map to enable different result codes. Linked to ATW      when ATW=1.      Bit   Value   Meaning      0–1   1      not used      2     4      Enables CARRIER messages only.      3     8      Enables CARRIER+PROTOCOL messages only.      4     16     not used      5     32     Enables CARRIER+PROTOCOL+COMPRESSION                   messages. (default) T   Enable tone (DTMF) dialing     Sets the default dialing mode to Touch-Tone mode. Can be     used in dial string (default). Vn  Verbalize     The V command allows you to choose the way you want to     display result messages: as code numbers or as English words.     Unless these messages are being read by a program that does     not easily recognize strings of characters, the default setting     (V1) is recommended   0 Displays result messages as code numbers (nonverbal).   1 Displays result messages as English words (verbal). (default) Verbalize result codes   0 OK Command is correct and has been completed   1 CONNECT Connection established   2 RING Incoming ring detected   3 NO CARRIER No connection or lost the carrier   4 ERROR Bad command   5 CONNECT 1200 Connection established at 1200 bps   6 NO DIALTONE Dial tone not detected in S7 seconds   7 BUSY Busy tone detected   8 NO ANSWER See ATD . . .@. . .  10 CONNECT 2400 Connection established at 2400 bps  11 CONNECT 4800 Connection established at 4800 bps  12 CONNECT 9600 Connection established at 9600 bps  13 CONNECT 14400 Connection established at 14400 bps  15 CONNECT 7200 Connection established at 7200 bps  16 CONNECT 12000 Connection established at 12000 bps  24 CONNECT 300/REL Connection with MNP 300 bps  25 CONNECT 1200/REL Connection with MNP 1200 bps  26 CONNECT 2400/REL Connection with MNP 2400 bps  27 CONNECT 4800/REL Connection with MNP 4800 bps  28 CONNECT 9600/REL Connection with MNP 9600 bps  29 CONNECT 7200/REL Connection with MNP 7200 bps  30 CONNECT 12000/REL Connection with MNP 12000 bps  31 CONNECT 14400/REL Connection with MNP 14400 bps Protocol negotiation progress codes that work with ATW1 and S95.  40 CARRIER 300 Carrier detected at 300 bps  46 CARRIER 1200 Carrier detected at 1200 bps  47 CARRIER 2400 Carrier detected at 2400 bps  48 CARRIER 4800 Carrier detected at 4800 bps  49 CARRIER 7200 Carrier detected at 7200 bps  50 CARRIER 9600 Carrier detected at 9600 bps  51 CARRIER 12000 Carrier detected at 12000 bps  52 CARRIER 14400 Carrier detected at 14400 bps  66 COMPRESSION: CLASS 5 MNP class 5  67 COMPRESSION: V.42BIS V.42 bis compression  69 COMPRESSION:NONE No compression  70 PROTOCOL:NONE Asynchronous mode  77 PROTOCOL:LAP-M Error control mode with LAP-M protocol  80 PROTOCOL:ALT Error control mode with MNP protocol 128 MODEM IN USE Modem already in use for this or another     application Wn  Progress result codes     The ATW setting determines whether progress result codes     are displayed in addition to the ATX codes. Register S95     determines which progress result codes will be displayed.   0 Progress codes 40 through 80 disabled.   1 Progress codes 40 through 80 enabled. (default)   2 Progress codes enabled; identical to W1.     When writing a CCL script, pay attention to result codes for     scripts that require a specific response. If progress codes     are enabled, the following strings appear on the screen during     a connection (in this example, V.22 bis connection with no     error control):         CARRIER 2400         PROTOCOL:NONE         CONNECT 2400 Xn  Active result code     The result codes listed in Vn are divided into subsets that     can be selected by the X command. Dial tone detection is     enabled by X2 and X4. Busy tone detection is     enabled by X3 and X4. The commands X0, X1, and     X3 are appropriate for blind dialing. Blind dialing means the     modem dials out even though a dial tone cannot be detected.   0 Selects result codes 0 through 4 and 8.   1 Selects result codes 0 through 5, 8, and 10 through 28.   2 Selects result codes 0 through 6, 8, and 10 through 28.   3 Selects result codes 0 through 5, 7, 8, and 10 through 28.   4 Selects all result codes. (default) Yn  Remote break handling     This command sets modem behavior for responding to a long     break signal received from a remote modem:         Greater than 1.6 seconds for an asynchronous connection         An attention frame for MNP or V.42.   0 The modem ignores any long breaks received from the remote     modem. (default)   1 On receiving a long break from the remote modem, the modem     goes on-hook (hangs up), and returns to command state.   2 On receiving a long break from the remote modem, the modem     returns to command state, but remains connected to the remote     modem (does not hang up). Zn  Reset     The Z command tells the modem to perform a software reset.   0 Loads Profile 0 into the active profile.   1 Loads Profile 1 into the active profile. &Cn DCD options     Since bus modems have no DTE-DCE serial interface, this     command has no effect and remains for scripting compatibility.   0–2 Return OK. &Dn DTR options     Bus modems do not have a DTRline. For bus modems, an on-to-     off DTR transition occurs when you close the connection tool or     the application currently using the modem. In this case, the     modem goes on-hook.     This command has no effect and remains for scripting     compatibility.   0-3 Return OK. Default value is 3. &F  Recall default profile     The current active profile is replaced by the default factory     configuration. &Gn Guard tones     This command specifies whether guard tones should be     transmitted. Guard tones are used in some telephone systems     to allow proper data transfer over the network. Guard tones are     not used in the United States.   0 Disables guard tone. (default)   1 Same as 2.   2 Sends 1800 Hz guard tone. &Kn Local flow control     This command specifies which kind of local flow control is     used. Since bus modems have built-in flow control mechanisms     between the DTE and the DCE, this command has no effect. Flow     control characters generated by the application software are     always passed to the line.     This command has no effect and remains for scripting     compatibility.   0-5 Respond OK, no action taken &Ln Switched/Leased line     This command affects the modem’s behavior during the call     setup and the carrier handshake phases at the beginning of a     connection.   0 Selects switched (dial-up) line. (default)   1 Selects conditioned leased line. &Pn Pulse mode make/break ratio   0 Sets the dial pulse make/break ratio at 39%/61%. (default)   1 Sets the dial pulse make/break ratio at 33%/67%. &Qn Connection mode     This command allows you to enable and disable error control     mode. The &Q command setting has precedence over \N     command setting and registers S36 and S48.   0 Asynchronous mode (no error control, disables V.42 and MNP).   5 Error control mode Instructs the modem to make a connection     using V.42/MNP, and fallback as necessary. (See S36 and S48     registers) (default) &Rn CTS/RTS     Since bus modems have no DTE-DCE serial interface, this     command has no effect and remains for scripting compatibility.   0–1 Return OK. &Sn DSR     Since bus modems have no DTE-DCE serial interface, this     command has no effect and remains for scripting compatibility.   0–2 Return OK. &Tn Self-tests     The following diagnostic tests are provided. These tests are     available only when no error protocol is engaged. The duration     of each test is controlled by register S18.   0 Terminate the test Used to terminate (escape from) a test in     progress and return to command state, if S18=0.   1 Local analog loopback Initiates a local analog loopback test.     The escape sequence must be entered to terminate this test.     This mode tests the local modem and the local data terminal     equipment.   3 Local digital loopback Initiates a local digital loopback test.     The modem echoes characters back to the remote modem     exactly as received.   4 Enable the remote digital loopback Enables the modem to     respond to a remote modem attempting to place it in digital     loopback test. If a remote modem places the local modem in     remote digital loopback mode, the local modem echoes     characters back to the remote modem exactly as received from     the remote modem.   5 Disable the remote digital loopback Disables the modem from     responding to a remote modem attempting to place it in the     digital loopback mode.   6 Remote digital loopback test In this mode, characters sent to     the remote modem are echoed back to the local modem exactly     as they were received by the remote modem. This mode tests     both local and remote modems and the telephone circuits.   7 Remote digital loopback with self-test Initiates a Remote     Digital Loopback (like &T6) with self-test data pattern     generation and error checking.   8 Local analog loopback with self-test Initiates a Local Analog     Loopback (like &T1) with self-test data pattern generation and     error checking.     The tests terminate when an AT&T0 command is issued or when     register S18 expires. In the self-test mode, an error counter     counts the number of errors and sends the final result to the     host at the end of the test. The maximum number of errors that     can be counted is 255.     Note: &T1 takes an optional parameter (a single character, A     or O) to indicate whether the analog loopback must be done in     originate (default) or answer mode. &Un Trellis coding     Enables/disables Trellis code modulation in V.32.   0 Enable Trellis coding. (default)   1 Disable Trellis coding. &Vn Display profiles     Displays the following information:         Active profile         Stored profile 0         Stored profile 1         Stored telephone numbers (See AT&Z.) &Wn Profile saving     This command saves the current active profile:   0 Saves the active profile into profile 0.   1 Saves the active profile into profile 1. &Xn Synchronous clock source     Ignored. Always returns OK. The modem does not support     synchronous modes. &Yn Specify start-up profile     Allows choosing between two different configurations at     start-up.   0 Specifies saved profile 0 as start-up configuration.   1 Specifies saved profile 1 as start-up configuration. &Zn=s Store phone number     Stores the dial string s (64 characters maximum) in location n.     The value of n can be equal to 0, 1, or 2. Note that the dial     string s is constructed in the same fashion as the ATD     command. It therefore must be the last command on the     command line and have no other characters following the dial     string. MNP-specific AT commands \Bn Send break     Send a break on the line for n times 100 milliseconds (n ranges     from 1 to 9). %Cn Compression enable Enables/disables MNPClass 5 data     compression during MNP reliable connections.   0 Disables data compression.   1 Enables MNP 5 data compression. (default) \Gn DCE flow control     Enables/disables modem-to-modem flow control. Coupled with     \X, which determines if flow control characters are passed     through or filtered.   0 Disables modem-to-modem flow control. (default)   1 Enables modem-to-modem flow control. \Nn MNP feature selection     Determines whether MNPerror control is used in connections.     The \N command setting also updates register S36. The &Q     command setting has precedence over \N command setting and     registers. 0-1 Normal mode MNPdisabled.   2 Reliable mode The modem will interrogate the remote modem     for MNPcapabilities. If the remote modem does not support MNP,     the local modem hangs up.   3 Auto-reliable mode The modem interrogates the remote modem     for MNPcapabilities. If the remote modem supports MNP, a     reliable connection is established. If the remote modem does     not support MNP, a normal connection is established. (default) \O  MNP link negotiation     Treated as ATO0 command. Modem returns to on-line state.     MNP Link is not negotiated. \Tn Inactivity timer     Where n is a decimal integer between 0 and 90 specifying     minutes. Sets the number of minutes the modem waits before     automatically hanging up when data is not sent or received. The     default option n=0 disables the timer. \U  MNP link negotiation     Treated as ATO0 command. Modem returns to on-line state.     MNP link is not terminated. \Vn MNP result code   0 Disables modified MNP result codes. (default)   1 Enables modified standard MNP result codes 24 to 28.   2 Returns OK; no effect. \Xn Flow control processing   0 No pass-through flow control. If modem-to-modem flow control     is enabled, AT\G1, XON/XOFF characters received from the line     are filtered out of the data stream; they are not passed to the     DTE. (default)   1 Pass-through flow control. If modem-to-modem flow control is     enabled, AT\G1, XON/XOFF flow control characters received     from the line are passed through to the DTE. \Y  MNP link signaling     Treated as ATO0 command. Modem returns to on-line state.     MNP link is not negotiated. \Z  MNP termination     Treated as ATO0 command. Modem returns to on-line state.     MNP link is not negotiated. -------- For changes, corrections or suggestions, please contact me at my America Online address Duo Dave, or Internet DuoDave@aol.com. Portions of this document is ©1993 by Apple Computer, Inc.