This file comes from Apple's Express Modem documentation. I didn't have time to format it up properly, so my apologies for the PRE text. Also, I don't know how current this information is, or how universal it is. If you find it useful, great, but don't assume it's the final word on anything. -Adam
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 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 (
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).
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.
; Return to local command state after dialing
The semicolon (;) modifier forces the modem back to the
local command state. Placing a semicolon at the end of the
dial string permits using the modem as a dialer and dialing
in two or more steps. You may also force the modem to ignore
the dial tone (blind dialing) by starting the dial string
with ";D". This modifier may also be used in Fax Sender,
AppleLink, and other communications applications.
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 modemıs 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 modemıs 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.
1 Connect at speed set in S37. Fallback if necessary. (default)
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 modemıs 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 doesnıt
support V.42.
3 Makes asynchronous connection. No error control. Same as
AT&Q0.
4 Attempts V.42 connection. If attempt fails, attempts MNP
24 connection. If attempt fails, then hangs up.
5 Attempts V.42 connection. If attempt fails, attempts MNP
24 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
01 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.
02 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 modemıs 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.
01 Return OK.
&Sn DSR
Since bus modems have no DTE-DCE serial interface, this
command has no effect and remains for scripting compatibility.
02 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.
Last modified in Feburary, 1997 by Adam C. Engst.
Copyright 1997, Adam C. Engst
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