%Cn -- Enable/Disable Data Compression

%En -- Auto-Retrain control

&Cn -- DCD Control

&Dn -- DTR Option

&Fn -- Recall Factory Profile

&Gn -- Select Guard Tone

&Kn -- Data Flow Control (Most non-US Robotics Modems)

&Kn -- Enables/Disables Data Compression (Texas Instruments, US Robotics)

&Qn -- Communication (Sync/Async Mode)

&Rn -- RTS/CTS (Hardware) Flow Control

&Tn -- Test Mode

&V -- View Configuration

&Wn -- Store User Profile

&Yn -- Default User Profile

&Zn=x -- Store Phone Number

)Mn -- Cellular Power Level Adjustment

*Hn -- Link Negotiation Speed

+++ -- Escape Sequence

+MS -- Select Modulation

:En -- Compromise Equalizer Setting

? -- Read Currently Selected S Register

@Mn -- Initial Cellular Power Level Setting

\An -- Select Maximum MNP Block Size

\Bn -- Transmit Break

\Gn -- Modem to Modem (Software) Flow Control

\Ln -- Select MNP Block/Stream Mode

\Nn -- Protocol Negotiation Selection

A -- Answer

A/ -- Re-execute Command

Bn -- CCITT or Bell Selection

Cn -- Carrier Control

Dn -- Dial

En -- Command Echo

Fn -- Select Modulation

Hn -- Disconnect (Hang-up)

In -- Identification

Ln -- Speaker Volume

Mn -- Speaker Control

Nn -- Automode Enable (Automatic Line Speed Detection)

On -- Return to On-Line Data Mode

P -- Set Pulse Dial Default

Qn -- Result Code On/Off

Sn -- Select a Specific S Registe

Sn=x -- Write an S Register Value

Sn? -- Read an S Register

T -- Set Tone Dial Default

Vn -- Result Code Format

Wn -- Negotiation Progress (Connect Message) Control

Xn -- Extended Result Code

Yn -- Long Space Disconnect

Zn -- Modem Reset

+++ (Escape Sequence)

This command re-executes the previous command processed by the modem.

In (Identification)

This command instructs the modem to return its product identification information.

I0 -- Returns the product code.

I1 -- Reports the 3 digits pre-computed ROM checksum code.

I2 -- Calculates a checksum of the modem firmware ROM and indicates OK or ERROR for the checksum validity.

I3 --Returns the modem ROM version.

I4 -- TBD

I5 -- TBD

I6 -- Returns the modem data pump model.

Easiest way to view this information on a win95/98 machine is to go to the control panel, modems, highlight your modem, click diagnostics, highlight the port the modem is on, and click more info. This will show you the whole range of ATI commands and is of great help when faced with trying to figure out what kind of modem is in your machine and possibly the driver of that modem.

This command resets the modem and recalls the stored configuration as defined at power on time.

Z0 -- Reset and recall stored user profile 0.

Z1 -- Reset and recall stored user profile 1.

Most usually only ATZ is used.

&Fn (Recall Factory Profile)

This command reloads the factory default profile.

&F0 -- Recall Factory Profile 0. Factory Profile 0 contains the default values from the modem chipset supplier.

&F1 -- Recall Factory Profile 1. Factory Profile 1 contains the default values defined by the product manufacturer.

L0,1 -- Selects low speaker volume.

L2 -- Selects medium speaker volume.

L3 -- Selects high speaker volume.

M0 -- The speaker is always off.

M1 -- Enables the speakerduring call establishment, but off once the carrier is detected.

M2 -- The speaker is always on.

M3 -- Disables the speaker during the dialing period and receiving carrier, but on during answering.

This command controls the modem response to the serial port's Data Terminal Ready (DTR) signal.

This command interprets the ON and OFF transitions of the DTR signal from the DTE in accordance with the parameters as defined by n.

This command determines how the modem controls data flow between the system and the modem. For example, if the speed between the system unit and the modem is 19200 bps, and the speed between the local and remote modem is 2400 BPS, the transmit buffer of the modem is likely to be overflow when the system is sending large amounts of data. To prevent an overflow and subsequent loss of data, the modem either sends a XOFF character or drops the CTS signal to signal that the system should stop data sending. When enough space is available in the modems transmit buffer, the modem either sends a XON character or raises CTS to signal that application could resume data sending. For binary data transfer CTS/RTS flow control should be selected since the modem cannot distinguish the user's data from XON/XOFF characters. Flow control is not used for direct mode connection.

&K0 -- Disables flow control.

&K1 -- Error

&K2 -- Error

&K3 -- Enables RTS/CTS flow control. Flow control is active in both sending and receiving direction.

&K4 -- Enables XON/XOFF flow control. Flow control is active in both sending and receiving direction.

&K5 -- Enables transparent XON/XOFF flow control. XON/XOFF character which is sent from the system unit will be processed for flow control and also sent to the remote modem. Flow control is active in both sending and receiving direction.

&K6 -- Enables both RTS/CTS and XON/XOFF flow control.

&K0 -- Data Compression Enabled &K1 -- Auto Enabled/Disabled &K2 -- Data Compression Enabled &K3 -- MNP5 Compression Disabled

This command determines how the modem controls CTS (Clear to Send). CTS operation is modified if hardware flow control is selected.

&R0 -- In synchronous mode, CTS tracks the state of RTS. In asynchronous mode, CTS acts according to V.25 handshake.

&R1 -- In synchronous mode, CTS is always ON (RTS transitions are ignored). In asynchronous mode, CTS will only drop if required by flow control.

This extended-format command selects the modulation and, optionally, enables or disables automode, specifies the lowest and highest connection rates.

The command format is:

+MS=[mod],[automode],[min_rate],[max_rate],[x_law],[rb_signaling]

+MS=11,1 disables k56flex and V.90 on some Rockwell modems and enables V.34 (33.6)

+MS=V34 disables V.90 on some Rockwell HCF chipset modems and enables V.34 (33.6)

+MS=k56flex disables V.90 on some Rockwell HCF chipset modems and enables k56flex

+MS=V90 enables V.90 on some Rockwell HCF chipset modems.

This command displays the current active configuration, stored user profiles, and the first four stored telephone numbers.

&Cn (DCD Control)

This command controls the behavior of the DCD (Data Carrier Detect) signal of the internal serial port.

&C0 -- DCD is always on.

&C1 -- DCD will track the state of the data carrier from the remote modem.

&W0 -- Store active configuration as user's profile 0.

&W1 -- Store active configuration as user's profile 1.

L Dials the last dialed number.

P Pulse (rotary) dial

R Originates call using answer (reverse) frequencies.

Sn Dials the phone number string stored in NVRAM at position n (n = 0*3). Phone numbers are stored with the &Zn=s command.

T Tone dial

, (Comma) Pause, See S8 definition; which it�s linked to.

; (Semicolon) Return to Command mode after dialing.

" Dials the letters that follow (in an alphabetical phone number).

! (Exclamation point) Flashes the switch hook.

/ Delays for 125 ms. before proceeding with dial string.

W Wait for second dial tone (X2 or X4); linked to S6 register.

@ Dials, waits for quiet answer, and continues (X3 or higher).

$ Displays a list of Dial commands.

eg: ATDP - Dials on a pulse line.

ATDT - Dials on a touch tone line.

ATDT5551234 dials 555-1234 on a touch tone line.

&Y0 -- Selects power up configuration as user's profile 0.

&Y1 -- Selects power up configuration as user's profile 1.

This command stores up to 4 telephone number dial strings into one of 4 non-volatile memory locations specified by n.

n: Entry number (range 0-3)

x: dial string less than 45 digits (including dial modifiers)

&G0 -- No Guard Tone, U.S. and Canada

&G1 -- 55o Hz Guard Tone, some European counties, requires B0 setting sometimes

&G2 -- 1800 Hz Guard Tone, U.K., requires B0 setting.

%C0- Disables data compression.

%C3- Enables both V.42bis and MNP5 data compression.

W2- Used to report the type of connection negotiation progress, protocol, and other communication techniques. Reports results from DCE (Modem to modem).

X3- Lets you dial out without worrying about dialtone detection. Busy detect enabled and dialtone detect disabled.

&Q0- Communicate in asynchronous mode (communication without error correction).

&Q8- Communicate in MNP error-correction mode.

&Q9- Communicate in V.42 error correction mode. If V.42 is not achieved, then MNP2-4 will be attempted.

\N0- Disable error correction. Speed buffering will be enabled.

\N3- Enable auto-reliable mode: V.42 LAPM or MNP4 error correction.

\N4- Enable V.42 LAPM error correction.

\N5- Enable MNP4 error correction.