Manuals

Command Set: Xircom® RealPort™ Ethernet 10/100+Modem 56 User's Guide

	Introduction to Modem AT Commands		AT Command Reference
	Special Commands

Introduction to Modem AT Commands

With the exception of the special commands, all commands must be preceded by the AT attention code (or command prefix) and terminated by pressing the <Enter> key.

The modem responds with the result code OK, which means it understands and can execute the command, or with ERROR, which means that the modem does not understand the command or that the command is invalid.

The modem must be in command mode when any command other than the online escape sequence is entered. Commands entered when the modem is in online mode are treated as data and transmitted as such to the modem at the other end of the line.

Some commands are used in coordination with S-Registers.

Special Commands

+++ Online Escape Sequence

The escape sequence is used to switch to command mode from online mode during a session with a remote modem. Type three �plus signs.� The escape sequence is not preceded by the AT command prefix, nor does it require the <Enter> key. The setting of S-Register S2 determines the ASCII character used. S2=43 is the default (the �+� sign). 0–127 are valid. To disable the command, set S2 to a value greater than 127. Use the ATO ( �AT� and letter �oh�) command to return to online mode.

Insert a pause before and after the escape sequence to prevent misinterpretation of the escape sequence as data. Use S-Register S12 to set the length of the pause.

A/ Repeat Last Command

The A/ command causes the modem to repeat the last command string. The command executes as soon as / is typed. It does not require the AT command line prefix, nor does it need to be followed by <Enter>.

AT Command Reference

A Answer

The ATA command causes the modem to go off-hook and respond to an incoming call by generating a carrier signal and starting the handshaking process. This must be the only command or the final command in the command line.

If the handshaking process is successful and a connection is established, the normal CONNECT message is displayed. If the carrier signal is not detected within the time specified in S-Register S7, a NO CARRIER result code is displayed.

Bn Select Communications Standard

The ATBn command selects the communication standard (ITU or Bell) to be used by the modem, as follows:

Break (Escape) command

See "Special Commands."

Cn Carrier Control

The ATCn command, where n is 1, guarantees backward compatibility with communications software that issues the C1 command. C0 is not supported; it may set some modems to "receive only mode."

Dn Dial A Telephone Number

The ATDn command is used to dial a telephone number. The n represents a dial string consisting of dial digits/characters and dial modifiers (see below) and must not exceed 40 characters. Spaces, hyphens, and parentheses can be used for clarity, but they are ignored by the modem.

The Dial command can be used for either pulse (rotary) or tone dialing. The dial digits/characters are 0 - 9 A B C D # *. The characters A B C D and the symbols # and * represent specific tone pairs and can be used only when tone dialing. These characters and symbols are ignored when pulse dialing is used. Some countries restrict or prohibit the use of some of these characters.

Dial modifiers are recognized by the modem only when they are part of a dial string following the ATD command. Possible dial modifiers are:

En Echo Command

The ATEn command, where n represents 0 or 1, determines if the commands you issue through the keyboard to the modem in command mode are displayed (echoed) on your computer�s monitor screen.

If the commands you type are not displayed on your monitor screen, your software is set to expect character echo from the remote system. You can remedy this by typing in ATE1. If the commands you type are displayed on your monitor with the characters duplicated, LLIIKKEETTHHIISS, type in ATE0.

Hn Switch Hook Options

The ATHn command hangs up the modem or prepares it for dialing.

In Request ID Information

The ATIn command has various options which are used to instruct the modem to provide specific information about itself.

Ln Monitor Speaker Volume

The ATLn command, where n represents 0, 1, 2, or 3, is listed here for backward compatibility reference only. The volume of the monitor speaker is controlled by the laptop computer, not by the modem.

Mn Speaker On/Off Selection

The ATMn command, where n represents 0, 1, 2, or 3, enables or disables the transmission of sound signals from the modem to the computer speaker. (Sound production also requires that the computer speaker be enabled.)

Nn Negotiation of Handshaking Options

The ATNn command, where n represents 0 or 1, determines whether or not the sending modem performs a negotiated handshake when the speed of the answering modem is different from that of the sending modem.

On Online Command

If the modem has been switched to command mode, the ATO0 command will return it to the online mode with the existing connection.

P Select Pulse Dialing

The ATP command instructs the modem to use pulse (rotary) dialing. This mode will remain in force for all dialing procedures unless an ATT command is issued or the dial string contains a T dial modifier.

Qn Result Code Display Options

The setting of the ATQn command, where n represents 0 or 1, determines whether or not result codes (such as OK, CONNECT, RING, NO CARRIER, and ERROR) are displayed on your PC�s screen.

Repeat command

See "Special Commands."

T Select Tone Dialing

The ATT command instructs the modem to use tone dialing. This mode will remain in force for all dialing procedures unless an ATP command is issued or the dial string contains a P dial modifier. Tone dialing is the factory-default setting.

Vn Result Code Format Options

The ATVn command, where n represents 0 or 1, determines if result codes are displayed as numeric (short form) codes or words (long form). Numeric result codes contain only one or two digits and this form could be used, for example, when the modem is controlled by a software terminal emulation program that uses script files. See the list at the beginning of this topic showing result codes in both long and short formats.

Type the command ATV or ATV0 to select numeric result codes. The factory default is to display the result codes as words (ATV1). You should issue an ATV1 command either to reset the factory default after a change has been made or to select the long-form (word) result codes. Negotiation progress messages (extended result codes) are those with a numerical value of 40 or more.

Four other AT commands, two dial modifiers, and an S-Register are also directly involved in the generation and display of result codes. These are the ATQn, ATVn, ATWn, and ATXn commands, the ATDW and ATD@ dial modifiers, and S-Register S95.

Wn Negotiation Progress Message Selection

The ATWn command, where n represents 0, 1, or 2, works in conjunction with S-Register S95 to determine how that subset of the result codes�called negotiation progress messages or extended result codes�will be used to report the type of connection, protocol, and other communication techniques that resulted from handshaking and subsequent negotiation.

The options available to represent n in the ATWn command are:

Xn Result Code Set/Call Progress Option

The ATXn command, where n represents 0-4, controls how the modem responds to dial tone and busy signals and how it displays CONNECT result codes. The options available to specify with the ATXn command are:

Yn Long Space Disconnect Option

The ATYn command, where n represents 0 or 1, determines whether or not the modem will disconnect a call when it receives a long space (1.6 seconds Break) signal during a V.22bis connection.

Zn Recall Stored Profile

The ATZn command, where n represents 0, disconnects any call that is currently in progress and reloads the user configuration profile stored in nonvolatile memory as the active configuration profile.

&Bn V.32 Automatic Retrain Options

The Xircom modem always retrains. The automatic retrain feature cannot be disabled.

&Cn Data Carrier Detect (DCD)

The AT&Cn command, where n represents 0 or 1, selects the method by which the modem handles the carrier detect signal.

&Dn Data Terminal Ready (DTR) Options

The AT&Dn command, where n represents 0-3, controls how the Data Terminal Ready (DTR) signal is used by the modem.

&Fn Load Factory Settings

The AT&F command loads factory default parameters from ROM into the active configuration profile, replacing the parameters stored there. This command must be issued by itself. If it is used with another AT command, its function will be ignored.

The following options are set with &F5:

Local Factory Settings

&Gn V.22bis Guard Tone Selection

This option is for international use only. It is not used in North America. The AT&Gn determines which guard tone, if any, to transmit while in answer mode (transmitting in the high band). The value of n can be 0, 1, or 2. This parameter is set automatically for most countries that require it.

&Jn Auxiliary Relay Option

&Kn Local Flow Control Options

The AT&Kn command, where n represents 0-4, determines how the flow control between the computer and the local modem is handled.

&Mn Communications Mode

The AT&Mn command, where n represents 0-4, determines how the flow control between the computer and the local modem is handled.

&Pn Pulse Dial Make-to-Break Ratio Selection

The AT&Pn command, where n represents 0, 1, or 2, controls the ratio of the off-hook (make) to on-hook (break) interval used by the modem when it pulse dials.

&Qn Asynchronous Communications Mode

&Sn Data Set Ready (DSR) Options

The AT&Sn command controls the functions of the modem�s DSR circuits.

&Tn Self-Test Commands

The AT&Tn command allows the user to perform diagnostic tests on the modem.

&V View Configuration Profile

The AT&V command displays the contents of the active configuration profile.

&Wn Write Active Profile to Memory

The AT&Wn command, where n is 0, allows you to save a copy of the current active configuration profile to nonvolatile memory. This profile can be restored at any time by using the ATZ command or a power-up reset of the modem.

&Yn Select Stored Profile for Hard Reset

This command is included for compatibility with applications that use the &Y0 command. It does not affect the behavior of the modem.

&Zn=x Store Telephone Number

The AT&Zn=x command is used to store a telephone number for later dialing using the ATDS=n (dial stored number) command. In this command, n is 0 or 1 representing 2 storage locations and x is the stored number. The dial string may contain up to 40 characters.

\Gn Modem Port Flow Control

The AT\Gn command determines whether XON/XOFF flow control will be used.

\Jn Adjust BPS Rate Control

\Kn Break Control

The AT\Kn command determines how the modem processes a Break signal received from the local DTE during a connection (online).

\Nn Error Mode Control Selection

The AT\Nn command sets the type of error correction supported by the modem when sending or receiving data.

\Qn Local Flow Control Selection

The AT\Qn command sets the type of flow control used on the serial port to adjust for differences in modem port speed.

\Tn Inactivity Timer Limit

The AT\Tn command specifies length of time (in minutes) that the modem waits before disconnecting when no data is sent or received. The time period can be set at n = 0 - 255. A setting of zero disables the timer. As an alternative, the timer may be specified in S-Register S30. This function is only applicable in buffer mode.

\Xn XON/XOFF Pass Through

%B View Numbers in Blacklist

If blacklisting is in effect, the AT%B command displays the numbers for which the last call attempted in the past two hours failed. In countries that do not require blacklisting, this command returns ERROR.

%Cn Data Compression Control

The AT%Cn command determines the operation of V.42bis and MNP class 5 data compression. Online changes do not take effect until a disconnect occurs.

-Cn Data Calling Tone

Data calling tone is a tone of a certain frequency and cadence specified in V.25 that allows remotes data/fax/voice discrimination. The frequency is 1300 Hz with a cadence of 0.5 seconds on and 2 seconds off.

+GCAP Request Complete Capabilities List

This command displays one or more lines of information text, in a standard format, describing the basic capabilities of the modem. This allows a software package to determine which groups of extended-syntax commands the modem supports. The response may contain one or more of the following responses:

+GCAP=? may be used to determine whether the modem supports the +GCAP command: an OK response indicates support, ERROR indicates non-implementation.

+GCI Country of Installation

This command configures the modem for the country of use, selecting operational parameters and ensuring conformity to the requirements of the selected country�s telephone network. The +GCI parameter may only be changed when the modem is in an idle state. <T.35 code> refers to the 8-bit hexadecimal number next to the country in the list below. To determine which countries are currently supported, use AT+CGI=? The command will respond with the T.35 codes for the countries supported. To determine the current country setting, use AT+GCI? The command will respond with the T.35 code for the country selected.

To change the current country selection, use AT+GCI=<T.35 code>

+GMI Request Manufacturer Identification

This command displays one or more lines of information text, identifying the manufacturer of the modem. +GMI=? may be used to determine whether the adapter supports the +GMI command: an OK response indicates support, ERROR indicates non-implementation.

+GMM Request Model Identification

This command displays one or more lines of information text, identifying the modem model. +GMM=? may be used to determine whether the modem supports the +GMM command: an OK response indicates support, ERROR indicates non-implementation.

+GMR Request Revision Identification

This command displays one or more lines of information text, identifying the revision level of the firmware of the modem. +GMR=? may be used to determine whether the adapter supports the +GMR command: an OK response indicates support, ERROR indicates non-implementation.

+MS Modulation Selection

The AT+MS command controls data modulations and bit rates that may be negotiated between a local and remote modem. It accepts four subparameters.

Please read all restrictions and disclaimers.