1. Introduction The AT commands are used to control the operation of your modem. They are called AT commands because the characters AT must precede each command to get the ATtention of the modem. AT commands can be issued only when the modem is in command mode or online command mode.
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MT5634 Modem; AT Command Set You can issue several commands in one line, in what is called a command string. The command string begins with AT and ends when you press [Enter]. Spaces to separate the commands are optional; the command interpreter ignores them.
2. AT Command Summary Organization of AT Commands on the following pages: 1st, by the initial command character (&, +, %), 2nd, alphabetized by the second command character (Except for listing of AT). Command DS=y Sr=n &Cn &Dn &En &Fn &Gn &Kn &Ln...
3. AT Commands Command: AT Attention Code Values: Description: The attention code precedes all command lines except A/, A: and escape sequences. Command: [Enter] Key Values: Press the [Enter] (RETURN) key to execute most Description: commands. Command: A Answer Values: Description: Answer call before final ring.
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MT5634 Modem; AT Command Set Command: Ds Dial Values: s = dial string (phone number and dial modifiers) Default: none Description: Dial telephone number s, where s may up to 40 characters long and include the 0–9, *, #, , B, C, and D characters, and the L, P, T, V, W, S, comma (,), semicolon (;), !, @, ^ and $ dial string...
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Command: Hn Hook Control Values: n = 0 or 1 Default: Description: Command: In Information Request Values: n = 0–5, 9, 11 Default: None Description: Command: Mn Monitor Speaker Mode Values: n = 0, 1, 2, or 3 Default: Description: Command: Nn Modulation Handshake Values:...
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MT5634 Modem; AT Command Set Command: P Pulse Dialing Values: P, T Default: Description: Configures the modem for pulse (non-touch-tone) dialing. Dialed digits are pulsed until a T command or dial modifier is received. Command: Qn Result Codes Enable/Disable Values:...
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Command: Wn Result Code Options Values: n = 0, 1, or 2 Default: Description: Command: Xn Result Code Selection n = 0–7 Values: Default: Description: Command: Zn Modem Reset Values: n = 0 or 1 Default: None Description: Command: &Cn Data Carrier Detect (DCD) Control n = 0, 1, 2 Values:...
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MT5634 Modem; AT Command Set Command: &Dn Data Terminal Ready (DTR) Control Values: n = 0, 1, 2, or 3 Default: Description: &D0 &D1 &D2 &D3 Command: &En XON/XOFF Pacing Control Values: n = 12 or 13 Default: Description: &E12 Disables XON/XOFF pacing.
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Command: &Ln Leased Line Operation n = 0, 1, or 2 Values: Defaults: Description: &L0 &L1 &L2 Note: For &L1 and &L2, there is a 30-second window between power up and the starting of the leased line handshake. During this time, you can turn off the command, if desired. Command: &Pn Pulse Dial Make-to-Break Ratio Selection n = 0, 1, or 2...
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MT5634 Modem; AT Command Set Command: &Tn Loopback Test (V.54 Test) Commands Values: n = 0, 1, 3, 6 Default: None Description: The modem can perform selected test and diagnostic functions. A test can be run only when the modem is operating in non-error- correction mode (normal or direct mode).
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Command: \An Select Maximum MNP Block Size Values: n = 0, 1, 2, or 3 Default: Description: Command: \Bn Transmit Break Values: n = 0–9 in 100 ms units Default: Description: In non-error-correction mode only, sends a break signal of the specified length to a remote modem.
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MT5634 Modem; AT Command Set Command: \Nn Error Correction Mode Selection Values: n = 0–5, or 7 Default: Description: Command: \Qn Flow Control Selection Values: n = 0, 1, or 3 Default: Description: Command: \Tn Inactivity Timer Values: n = 0, 1–255...
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Command: \Xn XON/XOFF Pass-Through Values: n = 0 or 1 Default: Description: Note: This is also controlled via &E6 and &E7. Command: -Cn Data Calling Tone n = 0 or 1 Values: Defaults: Description: Command: %An Adaptive Answer Result Code Enable Values: n = 0 or 1 Default:...
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MT5634 Modem; AT Command Set Command: %DCn AT Command Control n = 0 or 1 Values: Default: Description: %DC0 The modem responds to AT commands. %DC1 The modem ignores AT commands. Note: The modem will respond to AT%DC for 10 seconds after power-up.
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Command: $EBn Asynchronous Word Length n = 0 or 1 Values: Default: Description: $EB0 $EB1 Command: $MBn Online BPS Speed Values: n = speed in bits per second Default: 28,800 Description: $MB75 $MB300 $MB1200 $MB2400 $MB4800 $MB9600 $MB14400 $MB19200 $MB28800 $MB33600 Command: $RPn Ring Priority vs.
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MT5634 Modem; AT Command Set Command: +VDR=x, y Values: Default: Description: Command: #CBAn Callback Attempts Values: n = 1–255 Default: Description: Sets the number of callback attempts that are allowed after passwords have been exchanged between modems. Command: #CBDn Callback Delay Values: n = 0–255...
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Command: #CBF? Callback Failed Attempts Display Values: Default: Description: Requests the number of failed callback passwords since reset or power-up. This number can be stored to nonvolatile memory using the &W command. Command: #CBFR Callback Failed Attempts Reset Values: Default: Description: Resets the number of failed callback passwords to 0.
MT5634 Modem; AT Command Set Command: #CBSn Callback Enable/Disable n = 0, 1, 2, or 3 Values: Default: Description: #CBS0 Disables callback security. #CBS1 Enables local and remote callback security. #CBS2 Enables remote callback security only. #CBS3 Disables callback security until local hang-up or reset.
4. S-Registers Certain modem values, or parameters, are stored in memory locations called S-Registers. Use the S command to read or to alter the contents of S-Registers (see previous section). Register Unit Range 1 ring 0, 1–255 1 ring 0–255 decimal 0–127 128–255...
MT5634 Modem; AT Command Set Register Unit Range decimal 0–19 decimal 0–23 decimal 0–1 Default Description Sets the maximum V.34 "upstream" speed at which the modem attempts to connect. 0 = maximum speed 1 = reserved 2 = 1200/75 bps...
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Register Unit Range decimal 7 or 128 seconds 0, 5–255 S108 decimal 0–3, 6, 7 Default Description Enables (7) or disables (128) LAPM negotiation. The following table lists the S36 and S48 configuration settings for certain types of connections. S48=7 S36=0, 2 LAPM or hang up S36=1, 3...
5. Result Codes In command mode your modem can send responses called Result Codes to your computer. Result codes are used by communications programs and can also appear on your monitor. Terse Verbose CONNECT RING NO CARRIER ERROR CONNECT 1200 NO DIALTONE BUSY NO ANSWER...
6.1.2. Setup MT5634 Modems are shipped with a default setup password (MTSMODEM). Because anyone who has the User Guide knows the default setup password, you should change the password and possibly also the remote configuration escape character.
MT5634 Modem; AT Command Set 6.1.2.1. Changing the Setup Password Open a data communications program such as HyperTerminal. In the terminal window, type AT#SMTSMODEM (or AT#Syyyyyy if you have replaced the MTSMODEM password with yyyyyy) and press [Enter]. The modem responds with OK if the setup password is correct and ERROR if it is wrong.
6.2. Country Code Configuration Different countries have different requirements for how modems must function. Therefore, before you use the modem, you must configure it to match the defaults of the country in which you are using it. If you are comfortable using AT commands, you can configure your modem using AT commands.
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