Command Guidelines
Each AT
command has a list of
possible parameters with
its default value.
The default value (in bold type)
is loaded at initialization, i.e. power
turn on or ATZ command. If a command requires a parameter but no parameter is entered, the modem assumes the parameter is zero.
Invalid commands or parameters return
the ERROR message.
The command line may contain
a single command or
a series of
commands. The commands may be separated by a space for readability. The command line can be up to 40
characters in length. The command line
is executed after a terminating
character is entered. The
default terminating
character is a carriage return
(ASCII 013), but this may be changed by writing a different value to
reg. S3.
The command line may be edited using
the backspace character (ASCII
008). This value may
be programmed using
the S5 register. However, the backspace will not work for values of 0
and greater than 127, or for the current
value of the terminating character. All command
lines must begin
with AT entered in capital or lower case letters. A
command line can be terminated at any time by issuing
CTRL-X (ASCII 018) after entering
AT attention code. The
command line will be
ignored and an OK result message will be issued. The A/
command may be used to repeat the last command line. The A/ does
not require a
terminating character or the AT attention code.
The escape code sequence returns the modem
to the command mode from the data mode.
A time delay must occur between
the last character transmitted and the first character of the escape
code. The guard time delay can be
changed by writing a value to register S12; (default 1 second).
The escape code character must occur three times in succession for an escape.
Parameters that are entered for the AT and
AT& commands are limited in value
to 0-255, where the parameter is "MOD"ed with 256. The
result must be
within the specified range; if it
is not, the ERROR message is issued.
Parameters entered for an
S register are also "MOD"ed
with 256 and the result is stored in the S register. Parameters that are out of range
are stored in
the S register, however, no
ERROR message is reported. Functionally, however, the
lower or higher limit is observed. Parameters entered for the AT\ and
AT% commands follow the same method,
except that if the parameter is out of range, the upper limit is stored
and no ERROR message is reported.
Table
AT Command Definitions
Command Function
A/ Re-execute Command.
ATA Answer Command.
ATBn
Set CCITT or Bell Mode.
Command options :
ATB0 = Selects
CCITT V.22 bis, V.22, and V.21 standards for
communication at 2400,
1200, and 300 bps.
ATB1 = Selects Bell 212A and 103 standards
for communication at 1200 and 300 bps.
ATB15=*Select
V.21 connection at 300 bps.
ATB16=*Select
Bell 103 connection at 300 bps.
ATCn Carrier Control.
Command options :
ATC0 =** Not permitted ; returns ERROR result code.
ATC1 = Normal transmit carrier switching
(preset).
ATDn
Dial.
The
ATD parameters are :
L
Dials the last dial string that was dialed.
P
Use Pulse Dialing. Placed
at the end of
the command string and before
the dial string.
Causes the modem to pulse dial the numbers.
T
Use DTMF Dialing. Placed at the end of the command string and before the
dial string. Causes the modem
to use DTMF tones to dial.
R
Reverse Mode. Allows the modem to call an
originate only modem by forcing the
call into "answer mode". Must be entered as the last character of the command string
(just before the <CR>).
!
Hookflash. Causes the modem to
go on-hook for 700 milliseconds and then off-hook.
@
Causes the modem to listen for 5
seconds of silence. If a 5 second
silence has
not been detected within the period
specified in S7 (default = 30 seconds),
the modem disconnects and returns the "NO ANSWER" result code.
If it detects
a busy signal, it returns a "BUSY" result code. If the 5 seconds
of silence is
detected,then the modem continues dialing the string.
W
Wait For Dial
Tone Before Dialing. Causes
the modem to wait for a dial tone up to the period of time specified in register
7 (default = 30 seconds) before dialing the
numbers that follow. If the modem
detects a dial tone
before the given time delay, it
continues to dial. Otherwise, it goes on-hook.
,
Pause During Dial. Inserted
between digits in a dial string. Causes the modem to pause for the value given by
register S8 (default = 2 seconds), before dialing the next digit. This delay can be used in
place of the "Wait For Dial Tone Before Dialing".
;
Return To Command Mode
After Dialing. Added to the end of the dial string. Causes the modem to remain in
the command mode after it dials the digits preceding the command.This allows the user
to issue additional dial
commands or dial
strings without overflowing the command buffer. The modem looks for the carrier after the final dial command is
issued."ATHn" aborts this command.
^ Turn On Calling Tone. Turns on the
periodic 1300 Hz calling tone if
originating the
call. Calling tone is enabled only on
a call-by-call basis.
S=n Dial Stored Number. Follows the dial
command string. Causes the modem to
dial a telephone number previously stored in directory location n using
AT&Zn command. If "ATD" is entered
without parameters, the modem goes off-hook and waits for carrier; if the handshake is not completed within the period
of time specified by
register S7(default = 30 seconds), the modem goes on on- hook. The ATD command will be aborted in progress upon
receipt of any
character from the DTE before
completion of the handshake.
ATE Command Echo.
Command options :
ATE0 = Inhibits the echoing of commands.
ATE1 = Enables the echoing of commands.
ATFn
On-Line State Character Echo.
Command options :
ATF0 = Error.
ATF1 = Disables on-line echo.
ATF2 = Reserved
ATF3 = Select V.23 line modeulation
ATF4 = Select V.22 or Bell 212A 1200 bps line speed
ATF5 = Select V.22 bis line modulation
ATF6 = Select V.32 bis or V.32 4800 line modulation
ATF7 = Select V.32 bis 7200
line modulation
ATF8 =
Select V.32 bis or V.32 9600
line modulation
ATF9 = Select V.32 bis 12000 line modulation
ATf10= Select V.32 bis 14400 line modulation
ATHn
Switch-Hook Control.
Command options :
ATH0 = Causes the modem to go on-hook
(hang up).
ATH1 = If modem is on-hook, modem goes off-hook, returns an OK response, and awaits further
commands.
ATIn Identification.
Command options :
ATI0 = Reports the product code.
ATI1 = Reports the checksum computed on
the firmware ROM.
ATI2 = Performs a checksum on the firmware
ROM and indicates OK or ERROR.
ATI3 = Reports firmware revision level.
ATI4 = Reports product capabilities.
ATI5 = Report the country code number
ATLn Speaker Volume.
Command options :
ATL0 = Selects low speaker volume.
ATL1 = Selects low speaker volume.
ATL2 = Selects medium speaker volume.
ATL3 = Selects high speaker volume.
ATMn Speaker Control.
Command options :
ATM0 = Speaker is always off.
ATM1 = Speaker goes off while the modem is
receiving a carrier signal from a remote modem.
ATM2 = Speaker is always on.
ATM3 = Speaker goes off while the modem is receiving a carrier
signal from a remote modem and while the modem is dialing.
ATNn Modulation
Handshake.
Command options :
ATN0 = Requires that the speed of the connection be that
specified by the value
held in S37; if S37=0, the speed of the connection must
match that at
which the last AT command was issued. If the selected speed can be achieved using
more than one comunication
standard (e.g. Bell 212A or CCITT
V.22 at 1200 bps), the modem also references the selection made with the ATB command.
ATN1 = Permits handshaking t occur at any
speed supported by both modems. Enables automode
detection. The ATB command is ignored
in this mode and the
modem attempts only CCITT
mode connections.
ATN2 = Originate: Handshake per S37 and
Bn; fallback Answer: Negotiabte per V.22 bis, V.22, and V.21
ATN3 = Originate: Handshake only per S37 and
BnAnswer:Negotiate per V.22bis, V.22, V.23, and V.21
ATN4 = Originate: Handshake only per S37 and Bn
Answer:Negotiate per
V.22bis, V.22, V.23, and V.21
ATN5 = Originate: Handshake per S37 and Bn; fallback Answer:
Handshake only
per S37 and Bn
ATOn Return to the On-Line
State.
Command options :
ATO0 = Causes the modem to return to the
data mode.
ATO1 = Causes the modem to return to the data mode and to
initiate a retrain
when operating at any speed.
ATP Set Pulse Dial as Default.
ATQn Result Code Display.
Command options :
ATQ0 = Allows the modem to send result
codes to the DTE.
ATQ1 = Prohibits the modem from sending result codes to the DTE. ATQ2 = Modem
returns result codes to the DTE
when originating a call; does
not return result codes when
answering a call.
ATSn? Reading S Registers.
ATSn=x
Writing to S Registers.
ATT Set Tone Dial as Default.
ATVn
Result Code Form (Message Control).
Command options :
ATV0 = Allows short-form (numeric) result
codes to be sent.
ATV1 = Allows long-form (verbose) result codes to be sent.
ATWn
Negotiation Progress Reporting.
Command options :
ATW0 = Error-correction call progress not
reported.
ATW1 = Error-correction call progress
reported.
ATW2 = Error-correction call progress not
reported.CONNECT XXXX message reports DCE speed.
ATXn
Extended Result Codes.
Command options :
ATX0 = Modem ignores dial tone and busy
signal. Sends CONNECT message
when a connection is
established by blind dialing. ATX1 = Modem ignores dial tone and busy signal.
Sends CONNECT XXXX message reflecting bit rate when a connection is
established by blind dialing.
ATX2 = Modem ignores busy signal but waits
for dial tone before dialing. If dial tone is not detected within 5 seconds, the NO DIALTONE message is sent. Sends CONNECT XXXX
message reflecting bit rate when a connection is established.
ATX3 = Modem ignores dial tone. Sends BUSY message if a busy signal is detected. Sends CONNECT XXXX message
reflecting bit rate when a connection is established by
blind dialing.
ATX4 = If dial tone is
not detected within 5 seconds, sends NO DIAL TONE message. If busy signal
is detected, sends BUSY message. Sends CONNECT XXXX message reflecting bit rate when aconnection is established.
ATYn Control Long Space
Disconnect.
Command options :
ATY0 = Disable long space disconnect.
ATY1 = Enable long space disconnect.
ATZn Reset. Causes the modem to disconnect and
performs a warm start.
AT&Cn Data Carrier Detect
(DCD) Option.
Command options :
AT&C0 =RLSD is ON regardless of the
state of the data carrier from the remote modem.
AT&C1 =RLSD follows the state of the
data carrier from
the remote modem.
AT&Dn Data Terminal Ready (DTR) Option.
The
action for the
event that follows DTR
loss is indicated in the
following table :
&D0 &D1 &D2 &D3
&Q0 NONE 2 3 4
&Q1 1 2 3 4
&Q2 3 3 3 3
&Q3 3 3 3 3
&Q4 1 2 3 4
The DTR-going-off events corresponding to
the action numbers in the above table are :
1. Modem disconnects and sends OK result
code.
2. Modem goes into command mode if in data mode and sends the OK
result code.
3. Modem disconnects, sends the OK result
code, and disables auto answer while DTR is OFF.
4. Modem performs a warm start (i.e. same
as ATZ command). This is the DTE/AT&D3 abort.
AT&F0
= Restore factory profile 0
AT&F1
= Restore factory profile 1
AT&Gn Set Guard Tone.
Command options :
AT&G0 = Disable guard tone generation.
AT&G1 = Disable guard tone generation.
AT&G2 = Enable 1800 Hz guard tone generation.
AT&Jn Telephone Jack
Selection.
Command options :
AT&J0 =Suitable for RJ-11, RJ-41S, or
RJ-45S type phone jack. The auxiliary relay
is never operated.
AT&J1 =Suitable for RJ-12 or RJ-13 type phone
jack. The A lead is connected to A1 lead while modem is off-hook. If AT&J0 is
selected, the auxiliary telco relay is opened.
If AT&J1 is selected and the modem is off-hook, the auxiliary telco relay
(A/A1) is closed (shorting A to A1).
AT&Kn DTE/Modem Flow
Control.
Command options :
AT&K0 = Disables flow control.
AT&K3 = Enables RTS/CTS flow control.
AT&K4 = Enables XON/XOFF flow control.
AT&K5 = Enables transparent XON/XOFF flow control.
AT&K6 = Enable RTS/CTS and XON/XOFF DTE/DCE flow control
AT&Ln Line Type.
Command options :
AT&L0 = Dial-up line.
AT&L1 = Leased line.
AT&Mn Asynchronous Communication Mode.
AT&Pn Dial Pulse Ratio.
Command options :
AT&P0 = 39% / 61% make/break ratio @ 10 pps.
AT&P1 = 33% / 67% make/break ratio @ 10 pps.
AT&P2 = 33% / 67% make/break ratio @ 20 pps.
AT&P3 =* 33% / 67% make/break ratio @ 20 pps.
AT&Qn Communication Mode.
Command options :
AT&Q0 =Selects asynchronous operation
in the Direct mode. In this mode, the DTE speed must match the telco line speed.
AT&Q1 = Selects synchronous mode 1 operation. Supports
terminals that are
able to communicate in both
asynchronous and synchronous protocols. Uses the
dial command to place a call in
asynchronous mode then switches to synchronous
mode once the connection is made. The modem goes on-hook and switches back to
the asynchronous mode when it detects an
ON-to-OFF transition on DTR or a loss of carrier from the remote modem exceeding the time interval given by
register S10 (default
= 1.4 seconds).
AT&Q2 = Selects synchronous mode 2 operation. Supports synchronous terminals with stored number dialing. The modem automatically dials a stored number when it detects an OFF-to-ON
transition on DTR. An asynchronous terminal
is still needed to save or change the phone number stored
in the NVRAM; the number is saved using the "AT&Z0=x" command. The modem dials the
number stored in the first entry.
The modem goes on-hook and switches back to the
asynchronous mode when an ON-to-OFF transition on DTR is detected or a loss of carrier occurs from the remote modem
exceeding the time interval given by register S10 (default = 1.4
seconds).
AT&Q3 = Selects synchronous mode 3
operation. This mode allows DTR to
act as a Talk/Data switch. The operator manually
initiates a call with DTR OFF, implying the modem is in Talk mode. To
complete the call, the operator
switches the modem to Data mode by
turning DTR ON after
the last number is dialed. The modem
goes on-hook and switches to the asynchronous mode
when an ON-to-OFF transition on DTR is detected or a loss of carrier occurs from the remote modem exceeding the time
interval given by register S10 (default = 1.4 seconds).
AT&Q4 =This command causes the modem
to issue OK result code but has no effect on operation.
AT&Q5 =Selects error correction mode.
Modem negotiates an error-correction link. The modem can be configured to either
disconnect or fallback to a normal asynchronous
connection if the link cannot be
negotiated (refer
to register S36).
AT&Q5 and S36=0 : same as AT\N2 (no
fallback).
AT&Q5 and S36=1 : same as AT\N3
(fallback) (see AT\N command).
AT&Q6 =Selects asynchronous operation
in Normal mode (Speed Buffering). In this mode, the DTE speed can differ from the
telco line speed.
AT&Rn RTS/CTS Option.
Command options:
AT&R0 =CTS tracks RTS. CTS
is turned ON in
response to an OFF-to-ON transition of RTS from the local DTE
after a delay period specified by register S26 in increments of 10
milliseconds (default = 0).
AT&R1 =The modem ignores RTS; CTS is
held ON.
AT&Sn Data Set Ready (DSR)
Option.
Command options :
AT&S0 =DSR is always on.
AT&S1 =DSR is turned ON at start of
handshaking and OFF when in a test mode or idle
state. DSR is turned OFF when carrier is lost.
AT&Tn Test and Diagnostic.
Command options :
AT&T0 =End test in progress. The
escape sequence must be issued to return the modem to the command
mode prior to sending this command. Subsequent issuing of the ATO
command while in the command mode will cause the local
and remote modems to return to normal data mode operation if the interrupted
test was digital loopback.
AT&T1 =Initiates local analog
loopback. This test verifies the working condition of the path between the local DTE
and the local modem. The characters received from the DTE are looped back to the DTE by the modem.
AT&T3 =Initiates remote digital
loopback locally. The characters received from the remote modem are looped back to the remote
modem by the local
modem. This test verifies the working condition of the path from a
remote modem, through a
local modem, and back to the remote
modem.
AT&T4 =Allows the modem to respond to
a request from a remote modem for a remote digital loopback test.
AT&T5 =Prohibits the modem from
granting a request from a remote modem for a remote digital loopback test.
AT&T6 =Initiates remote digital
loopback. The characters received from the local DTE are transmitted to the remote modem and
looped back from the remote modem to the local modem and
DTE. This test verifies the working condition of the path
between the local DTE and the remote modem.
AT&T7 =Initiates remote digital
loopback with self test. This test works similarly to AT&T6 except that the modem sends an
alternating zeros and ones
(0101) test pattern to the remote modem and continuously examines
the validity of
the returned data. The modem increments
an internal error
counter each time an error is detected. At the end of the test, the
modem returns a
3-digit error count to the DTE.
AT&T8 =Initiates local analog loopback
with self test. This test works similarly to AT&T7 except that the test pattern is
checked in the local analog loopback mode (as in
AT&T1). This allows a thorough
testing of the local modem
transmit and receive functions without an actual telco line
connection.
AT&V View Current Configuration and User
Profiles. Displays the active configuration and user profiles.
AT&Wn Store User Profile.
Command options :
AT&W0 = Save as user profile 0.
AT&W1 = Save as user profile 1.
AT&Xn
Clock Source Selection.
Command options :
AT&X0 = Internal timing. The modem
generates the transmit clock signal and applies it to the EIATXCLK output at the
serial interface.
AT&X1 = External timing. The local DTE
sources the transmit clock signal on the SPXEXTCLK input of the serial interface.
The modem applies this clock to the EIATXCLK output at the
serial interface.
AT&X2 =Slave receive timing. The modem derives the transmit clock
signal from the incoming
carrier and applies it to the EIATXCLK
output at the serial interface.
AT&Yn Designate Default User Profile.
Command
options :
AT&Y0 =Selects user profile 0.
AT&Y1 =Selects user profile 1.
AT&Zn=x
Store Phone Number. Stores a 36-digit dial string(x) in the specified entry(n)
or later dialing. (See ATDS=n command.)
AT\An
Maximum MNP Block Size.
Command options :
AT\A0 =Sets maximum block size to 64
characters.
AT\A1 =Sets maximum block size to 128
characters.
AT\A2 =Sets maximum block size to 192
characters.
AT\A3 =Sets maximum block size to 256
characters.
AT\Bn Transmit Break.
AT\Gn
Modem to Modem Flow Control.
Command options :
AT\G0 =Disables flow control (XON/XOFF).
AT\G1 =Enables flow control (XON/XOFF).
AT\Kn
Break Control.
Command options :
When a BREAK is received from the DTE
during Normal or MNP mode, the modem takes the following action: AT\K0,2,4 =
Modem enters the command mode (waiting for AT) without sending a BREAK to the remote modem.
AT\K1 =Modem clears the terminal and modem buffers and sends a
BREAK to the remote modem.
AT\K3 =Modem does not clear
the buffers but sends a BREAK to the remote modem.
AT\K5 =Modem sends a BREAK to the remote
modem in sequence with any transmitted data. When a BREAK is
received from the remote modem during Normal mode, the modem takes the
following action :
AT\K0,1 = Modem clears the terminal and
modem buffers and sends a BREAK to the local DTE.
AT\K2,3 = Modem does not clear
buffers but sends a BREAK to the local
DTE.
AT\K4,5 = Modem sends a BREAK in sequence
with any data being buffered. When a BREAK is received from the
DTE during Direct mode, the modem takes the followig action :
AT\K0,2,4 = Modem sends a BREAK to remote
modem and enters command mode
(waiting for AT).
AT\K1,3,5 = Modem sends a BREAK to remote
modem.
AT\Kn
Note: In LAPM, breaks are "timed", meaning the modem attempts
to
preserve the duration of the break when transmitting it to the
remote mo dem. IN MNP4, breaks are not
"timed", as MNP4 has no facility for maintaining the duration of the signal; a long break
is the same as a short
break.
AT\Ln MNP Block Transfer Control.
Command options:
AT\L0 =Uses Stream mode for MNP link
connections.
AT\L1 =Uses Block mode for MNP link
connections.
AT\Nn Operation Mode Control.
Command
options :
AT\N0 =Selects Normal (speed buffering)
mode.This option takes effect at physical connection time.
AT\N1 =Selects Direct (pass through) mode.This
option takes effect at physical connection time. If the parallel interface is
selected (SEREN = low), the AT\N1 is
interpreted as AT\N0 since Direct mode
is not available with the parallel interface.
AT\N2 =Selects reliable link mode. This
defines the modem-to-modem connection to require error
correction. If an attempt to establish the reliable link fails, the modem disconnects. This
command takes effect at physical connection time only. To establish MNP
after a physical connection, use the
AT\O, AT\U, or AT\Y command.
AT\N3 =Selects auto-reliable link mode. The modem will attempt an error-correction
connection but will fallback to normal mode
if unable to establish an MNP link. This command takes effect at physical
connection time only. To establish MNP
after a physical connection, use the AT\O, AT\U, or AT\Y command.
AT\N4 =Force LAPM mode
AT\N5 =Force MNP mode
AT%Cn Compression Control.
Command
options :
AT%C0 = Disables data compression.
AT%C1 = Enables data compression.
AT%C2 = Enable V.42 bis data compression
AT%C3 = Enable both V.42 bis and MNP 5
compression
AT%En
Enable/Disable Auto-Retrain.
Command options :
AT%E0 = Disables auto-retrain.
AT%E1 = Enables auto-retrain.
AT%L Report Received Signal Level.
AT%Q Report Line Signal Quality. Returns
the high-order byte of the calculated
Eye Quality Monitor (EQM)
value. The high-order byte can range from 0 to 255. However,
when the value is 8 or greater,
the modem will automatically
retrain if enabled by the AT%E1 command. The value for a normal
connection ranges from
about 0 to 2 and approaches 8 for a progressively poorer connection.
Parameters : None.
Default : None.
Result codes : OK
AT%TT PTT certification test signal
S REGISTERS
The
S registers affect various operating characteristics, they let
you obtain information about your modem, and let you test your
modem. Each register has a default
value, which you can read or change to fit your particular
requirements.
Table 3-1 shows the registers, their functions,
and their default values. Some
registers can have their values changed by commands.
All of
the factory default values may be loaded at any time by entering the AT&F
command.
Table 3-1. S Register Definitions
Register Function
S0 Number of
Rings till Auto-Answer. Establishes
the number of the rings required
before the modem answers the incoming calls. Setting this register to
zero disables auto-answer mode.
Range : 0-255 rings.
Default : 0.
S1 Ring Counter. Number of the rings which the
modem detects before it answers a call. If no rings occur over an eight-second
interval, this register is cleared.
Range : 0-255 rings.
Default : 0.
S2 Escape
Character. S2 holds the decimal value of the ASCII character used for
the escape character. The default value corresponds to an ASCII'+'. A value
over 127 disables the escape process, i.e. no escape character will be
recognized.
Range :
0-255, ASCII decimal.
Default : 43.
S3 Carriage Return Character. Sets the command
line and result code terminator character. Pertains to asynchronous operation
only.
Range :
0-127, ASCII decimal.
Default : 13 (Carriage Return).
S4 Line Feed Character. Sets the character
recognized as a line feed. Pertains to asynchronous operation only. The Line
Feed control character is output after the Carriage Return control character if
verbose result codes are used.
Range : 0-127, ASCII decimal.
Default : 10 (Line Feed).
S5 Backspace
Character. Sets the character recognized as a backspace. Pertains to
asynchronous operation only. The modem will not recognize the Backspace character if it is set to a value that is
greater than 32 ASCII. This
character can be used to edit a command line. When the echo command is enabled, the modem echoes back to the local DTE
the Backspace character, an ASCII space character and a second Backspace
character; this means a total of three
characters are transmitted each time the modem
processes the Backspace character.
Range : 0-32, ASCII decimal.
Default : 8 (Backspace).
S6 Wait Time for Blind Dialing. Sets the length of time to pause
after the modem goes off-hook and
before the modem dials the first digit of the telephone number. The modem always pauses
for a minimum of 2 seconds even if the S6 register is set to a value
less than 2 seconds. The "Wait For Dial Tone" call progress feature
(W in the dial string) will
override the value in register S6. If
option ATX2 or ATX4 is in effect, this
register is ignored.
Range : 2-255 seconds.
Default : 2.
S7 Wait for Carrier after Dial.
Defines two delay times :
1. During call establishment, this register establishes the time that the local
modem waits for carrier from the remote modem before hanging up.
2. Sets the length of time that the modem waits
when the "Wait For Dial Tone" call progress feature (W in the dial string) is in effect.
Range : 1-255 seconds.
Default : 50.
S8 Pause Time for Dial Delay. Sets the length
of time to pause when the modem encounters the "Pause During Dial"
call progress feature, i.e. the comma
(,).
Range : 0-255 seconds.
Default : 2.
S9 Carrier Detect Response Time. Determines
how long a carrier signal must be present before the modem recognizes it as a
carrier and turns on RLSD. As this time is increased, there is less chance to
detect a false carrier due to noise from the telco line.
Range : 1-255 tenths of a second.
Default : 6 (0.6 second).
S10 Lost Carrier to Hang Up Delay. Sets the length of time the modem waits
before hanging up after a loss of carrier. This allows for a temporary carrier
loss without causing the local modem to disconnect. When register S10 is set to
255, the modem functions as if a carrier is always present. S10 The actual
interval the modem waits before disconnecting is the value in register S10 minus the value in register S9. Therefore,
the S10 value must be greater than the S9 value or else the modem disconnects
before it recognizes the carrier.
Range : 1-255 tenths of a second.
Default : 14 (1.4 seconds).
S11 DTMF Tone Duration. Sets the duration of
tones in Dual Tone Multifrequency
(DTMF) dialing. This value has no effect on pulse dialing.
Range : 50-255 milliseconds.
Default : 95 milliseconds.
S12 Escape Code Guard Time. Sets the time
delay required immediately before and after entering the escape code. The time interval
between the sending of the first
and second, or the second and the third escape code character must be less than
the value of the guard time.
Range : 0-255 fiftieths of a second.
Default : 50 (1 second).
S13 Reserved.
S14 Bit Mapped Options. Indicates the status
of command options.
Default : 138(8Ah)(10001010b)
Bit 0 = This bit is ignored Bit 1 = ATE
0 = Disabled
1 = Enabled
Bit 2 = Quiet mode (Qn) = ATV
S15 Reserved.
S16 Bit
Mapped Test Options.
Indicates the test
in progress. The TML output is turned ON when S16 is non-zero to indicate that a test is in
progress. The AT&T0 command terminates any test and sets S16 to zero.
Default : 0
Bit 0 = Local analog loopback
(AT&T1)
0 = Disabled (default)
1 = Enabled
Bit 1 = Not used
Bit 2 = Local digital loopback
(AT&T3)
0 = Disabled (default)
1 = Enabled
Bit 3 = Remote digital loopback status
(AT&T4 and T5)
0 = Loopback off
1 = Loop-back in progress
Bit 4 = Remote digital loopback
(AT&T6)
0 = Disabled (default)
1 = Enabled
Bit 5 =Remote digital loopback with
self test (AT&T7)
0 = Disabled (default)
1 = Enabled
Bit 6 = Local analog loopback with self
test (AT&T8)
0 = Disabled (default)
1 = Enabled
Bit 7 = Not used
S17 Reserved.
S18 Test Timer. Sets the length of time your
modem conducts a test before returning to the command mode If this register is
zero,the test will not automatic
terminate; the test must be terminated from the command mode by issuing
an AT&T0 or ATH command.
Range : 0-255 seconds.
Default : 0.
S19 Reserved.
S20 Reserved.
S21 Bit Mapped Options. Indicates the status
of command options.
Default : 4(00000100b)
Bit 0 Bit 1
0 = AT&J0 Reserved
1 = AT&J1
Bit 2 Bit 3,4
0 = AT&R0 0 = AT&D0
1 = AT&R1 1 = AT&D1
2 = AT&D2
3 = AT&D3
Bit 5 Bit 6
0
= AT&C0 0 = AT&S0
1
= AT&C1 1 = AT&S1
Bit 7
0
= ATY0
1
= ATY1
S22 Bit Mapped Options. Indicates the status
of command options.
Speaker/Results Bit Mapped Options
Default : 117(75h)(01110101b)
Bit 0,1 Bit 2,3
0
= ATL0 0 = ATM0
1
= ATL1 1 = ATM1
2
= ATL2 2 = ATM2
3
= ATL3 3 = ATM3
Bit 4,5,6 Bit 7
0
= ATX0 Reserved
4
= ATX1
5
= ATX2
6
= ATX3
7
= ATX4
S23 Bit Mapped Options. Indicates the status
of command options.
Default : 55(37h)(00110111b)
Bit 0 Bit 1,2,3 - Local DTE Rate
0
= AT&T5 0 = 0-300 bps
1
= AT&T4 1 = 600 bps
2 = 1200 bps
3 = 2400 bps
4 = 4800 bps
5 = 9600 bps
6 = 19200 bps
Bit 4,5 Parity Option Bit 6,7
0
= even 0 = AT&G0
1
= not used 1 = AT&G1
2
= odd 2 = AT&G2
3
= none
S24 Inactivity Timer
Range: 0-255 seconds
Default: 0
S25 Delay to
DTR. Sets the lenghth of time,
in seconds, that the modem will ignore DTR
before hanging up. Its units are seconds for synchronous mode 1 and
one hundredths of a seconds
of a second for other modes.
Range: 0-255 (1 second for synchronous
mode 1;0.01
second otherwise.)
Default : 5.
S26 RTS to CTS Delay Interval. Pertains to
synchronous operation only. When CTS tracks RTS (AT&R0) and your modem
detects an ON-to-OFF transition on RTS, this register sets the time delay before your
modem turns CTS ON.
Range : 0-255 hundredths of a second.
Default : 1.
S27 Bit Mapped Options. Indicates the status
of command options.
Default : 73(49h)
Bit 0,1,3 Bit 2
0
= AT&Q0 0 = AT&L0
1
= AT&Q1 1 = AT&L1
2
= AT&Q2
3
= AT&Q3
4
= AT&Q4
5
= AT&Q5
6
= AT&Q6
Bit 4,5 Bit 6
0
= AT&X0 0 = ATB0
1
= AT&X1 1 = ATB1
2
= AT&X2
Bit 7 - Reserved.
S28 Bit Mapped Options
Default: 0
Bit 0 = V.23 split screen (\Wn) Bit 1 =
V.23 split screen direction
0 = Disabled(\W0) 0 = 75
Tx/1200 Rx(%F1)
1 = Enabled (\W1) 1 =
1200 Tx/75 Rx(%F2)
Bit 2 = Reseved (always 0).
Bit3,4= Puls dialing (&Pn)
0 = 39%-61% make/break ratio at 10 pulses per
second (&P0)
1 = 33%-67% make/break ratio at 10 pulses per
second (&P1)
2 = 39%-61% make/break ratio at 10 pulses per
second (&P2)
3 = 33%-67% make/break ratio at 10 pulses per
second (&P3)
Bit 5 = Reserved
Bit 6,7= MNP Link negotiation Speed
0 = Link negotiation at highest speed
1 = Link negotiation at 1200 bps
2 = Link negotiation at 4800 bps
S29 Flash Dial Modifier Time. Sets the length
of time, in units of 10 ms, that the modem will go on-hook when it encounters
the flash(!) dial modifier in the dial string. The time can be limited as it is a country dependent
parameter.
Range : 0-255 Default : 0 (Disabled)
S30 Inactivity Timer. Determines the length of time, in
ten-second intervals, that your
modem will wait before disconnecting
when no data is sent or received. In
MNP or V.42 mode, any data
transmitted or received will reset the timer. In other modes, any data
transmitted will reset the timer. The inactivity timer is inoperative in
synchronous mode.
Range : 0-255. Default : 0 (disabled).
S31 Bit Mapped Options
Default : 2
Bit 0
Bit 1 = Controls auto line speed detection Nn
Reserved 0 = Disabled (N0)
1 = Enabled (N1)
Bit 2,3 Control error correction
progress messages Wn
0 = DTE speed only (W0)
1 = Full reporting (W1)
2 = DCE speed only (W2)
Bit 3-7 Reserved
S32 XON Character. Sets the value of the XON
character
Range : 0-255 Default : 17
S33 XOFF Character
Sets the value of the XOFF character.
Range : 0-255 Default : 19
S34-S35
Reserved.
S36 Negotiation Failure Treatment. This register is read when the
S48 register contains the value 128 or
if an attempted error correction link fails. These fallback options are
initiated immediately upon connection if
S48=128.
Range : 0-7 if an invalid number is
entered, the number is accepted into the register, but S36 will act
as if the default value is entered.
Default : 7.
The S36 actions are :
S36=0
Modem disconnects.
S36=1
Modem stays on-line
and a Direct mode connection is
established.
S36=2
Reserved.
S36=3
Modem stays on-line
and a Normal mode connection is
established.
S36=4 An MNP connection is attempted
and if
it fails, your modem
disconnects.
S36=5
An MNP connection is attempted and if it fails, a Direct mode connection is established.
S36=6
Reserved.
S36=7
an MNP connection is attempted
and if it fails, a Normal mode connection is established.
S37 Desired Telco Line Speed. This
register determines the desired telco
line speed if the ATN0 command is in
effect.
Range : 0-7 if an invalid number is
entered, the number is accepted
into the
register, but S37
will act as if the default value
is entered.
Default : 0.
S37=0
Attempt to connect
at speed of
last AT command issued. For
DTE speeds greater than 2400 bps, your modem will attempt to connect at 2400 bps.
S37=1-3 Attempt to connect at 300 bps.
S37=4
Reserved.
S37=5
Attempt to connect at 1200 bps.
S37=6
Attempt to connect at 2400 bps.
S37=7
Attempt to connect in V.23 75/1200 mode.
S37=8
Attempt to connect at 4800 bps.
S37=9
Attempt to connect at 9600 bps.
S37=10 Attempt to connect at 12000 bps.
S37=11 Attempt to connect at 14400 bps.
S37=12 Attempt to connect at 7200 bps.
S38 Delay before Forced Disconnect (Error
correction mode only). This register specifies the delay between your modem's receipt of the ATH command to
disconnect (or ON- to-OFF transition of DTR if your modem is programmed to
follow the signal) and the disconnect operation. For an error-correction
connection, this register can be used
to ensure that data in your modem buffer is
sent before your modem
disconnects. If S38 is set between 0 and 254, your modem will wait that number
of seconds for the remote modem to acknowledge all
data in your modem buffer before disconnecting. If time expires before all data
is sent, the NO CARRIER result code will be issued to indicate that data has been lost. If all data is transmitted
prior to timeout, the response to the ATH0 command will be OK. If S38 is set to
255, your modem does not timeout, and continues to attempt to deliver data in
the buffer until the connection is lost, or the data is delivered.
Range : 0-255 seconds.
Default : 20.
S39 Flow Control.
Default : 3
Bit 0,2 Status of command option Bit 3-7
0 = No flow control
Reserved
3 = RTS/CTS (&K3)
4 = XON/XOFF (&K4)
5 = Transparent XON (&K5)
6 = Both methods (&K6)
S40 Bit Mapped Options (MNP). Indicates the
status of command options.
Range : None.
Default : 105 (01101001b)(non-MNP 10
models)
107 (01101011b)(MNP 10 models)
Bit 0 : MNP Extended Services (-Kn)
0 = Disable extended services (-K0)
1 = Enabled extended services (-K1)
Bit 1 : Enable fallback to
V.22bis/V.22(-Qn)
0 : Disable (-Q0)
1 : Enable (-Q1)
Bit 2 : Power Level Adjustment for
Cellular Use Mn
Bit 3-5 Break Handling (\Kn)
0 = \K0 1 = \K1
2 = \K2 3 = \K3
4 = \K4 5 = \K5
Bit 6-7 MNP Block Size(\An)
0 = 64 chars (\A0) 1 = 128
chars (\A1)
2 = 192 chars (\A2) 3 = 256
chars (\A3)
S41 Bit Mapped Options (MNP). Indicates the
status of command options.
Range : None.
Default : 3 (00000001b)
Bit 0,1
=AT%C
Bit 2,6
=AT%E
Bit 3
=AT\G
Bit 4
=AT\L
Bit 5,7
Reserved
S46 Protocol Selection. Controls selection of
compression.
Default : 138
The following actions are executed for
the given values :
S46=136 Execute error correction protocol with no compression.
S46=138 Execute error correction protocol with compression.
In addition to V.42 (V.42
bis), your modem also implements MNP5 data compression.
V.42 is used only with LAPM, and MNP5 only with MNP4.
S48 V.42 Negotiation Action. The V.42
negotiation process determines the capabilities of the remote modem. However,
when the capabilities of the remote modem are known and negotiation is
unnecessary, this process can be bypassed if desired.
Range : 0, 7 or 128 if an invalid number is entered, it is
accepted into the S register, but S48 will act as if 128 is entered.
Default : 7.
S48=0
Disable negotiation; bypass the detection and negotiation phases;
and proceed
with LAPM.
S48=7
Enable negotiation.
S48=128 Disable negotiation; bypass the
detection and negotiation phases ; and proceed at once with he fallback action
specified in S36. Can be used to force MNP.
S82 Break Handling Options. Break signals
provide a way for the user to get
the attention of the remote modem. The break type depends on the
specific application. LAPM specifies
three methods of break signal handling : in sequence, expedited, and
destructive.
Range: 3, 7, or 128 if an invalid
number is entered, it is accepted into the S register, but S82 will act as if the default value is entered.
Default : 128.
S82=3
Expedited : Modem sends a break immediately ; data integrity is
maintained both ahead
of and after the break.
S82=7
Destructive : Modem sends a break immediately; data being processed
by each modem at the time of the break is destroyed.
S82=128 In sequence : Modem sends a
break in sequence with any transmitted data; data integrity is maintained both ahead of and
after the break. (factory default.)
S86 Connection Failure Cause Code. When your
modem issues a NO CARRIER result code, a value is written to this S register to
help determine the reason for the failed conection. S86 records the first event that contributes
to a NO CARRIER message.
Default : none.
The cause codes are :
S86=0
Normal disconnect, no error occurred.
S86=4
Loss of carrier.
S86=5
V.42 negotiation failed to detect an error-correction modem at the
other end.
S86=6
No response to feature negotiation
S86=7
This modem is asynchronous only; the other modem synchronous only.
S86=8
No framing technique in common protocol.
S86=9 The modems could not find a common
protocol.
S86=10 Bad response to feature
negotiation.
S86=11 No sync information from remot
modem.
S86=12 Normal disconnect initiated by the
modem.
S86=13 Remote modem does not respond after
10 re-transmissions of the same message.
S86=14 Protocol violation.
S91 Programmable Transmit Levels. The
transmit level is adjustable in S91 from 0 dBm (U.S. default value)
to -15 dBm (Japan default value) in 1 dB increments for data transmission in both
synchronous and asynchronous operation.
This S register takes effect when the Japanese parameters are enabled (see
1.3.4) or a leased line is selected.
S91=0
0 dBm (default value for U.S.)
S91=1
-1 dBm
S91=2
-2 dBm
S91=14
-14 dBm
S91=15
-15 dBm (default value for Japan). The transmit level may not be changed once a
connection exists.
S92 Fax
Transmit Attenuation Level
Range : 0-15 dBm Default : 10
S95 Extended Result Codes. The bits in this register can be set to override some of
the ATWn command options. A bit set to a 1 in this register will enable the corresponding result code regardless of the
ATWn setting.
Bit 0 = CONNECT result code indicates DCE speed instead of
DTE speed.
Bit 1 = Append /ARQ to verbose CONNECT
XXXX result code if protocol is not NONE.
Bit 2 = Enable CARRIER XXXX result
code.
Bit 3 = Enable PROTOCOL XXXX result
code.
Bit 4 = Reserved.
Bit 5 = Enable COMPRESSION result code.
Bit 6 = Reserved.
Bit 7 = Reserved.
S99 Range : 0 : -15 Default : 10
FAX CLASS 1 AND CLASS 2 OPERATION
Fax Class 1 Command Definitions
Command Function
+FCLASS=n
Select Service Class. +Fclass=n command sets the active service class.
Parameters: 0-2
Default: 0
Command options:
+FCLASS=0 Select Data Mode
+FCLASS=1 Select Facsimile
Class 1
+FCLASS=2 Select Facsimile
CLASS 2
+F<command>?
Report Operating Capabilities. +F<command>=? can be used to determine the
operating capabilities of the modem. Typical responses are:
+FAE=? 0,1
+FCLASS=? 0,1,2
+FTM=? 3,24,48,72,96
+FRM=? 3,24,48,72,96
+FTM=? 3,24,48,72,73,74,96,97 ,98,121,122,145,146
+FRM=?3,24,48,72,73,74,96,97,98,121,122,145,146
+FAEn Data/Fax Auto Answer.
+FAEn allows the DTE to either restrict answering to class 1, or to
utomatically detect whether the calling station is a fax class 1 modem or data
modem, and answer
accordingly.
Parameters: 0,1
Default: 0
Command options:
n=0 The modem answers as a fax modem only.
n=1 The modem answers as fax or data
modem.
+FTS=n Stop Transmission and Wait.
+FTS=n causes the modem to determine a transmission
and wait for n 10 millisecond intervals before
responding with the OK result
code. An ERROR response code results if this command is issued while the modem
is on-hook.
+FRS=n Receive Silence. +FRS=n causes the modem
to report back to the DTE with an OK result code after
n10 millisecond intervals of silence have been detected on the line. This command is aborted if any character
is received from the DTE. The modem
discards the aborting character and issues an OK result code. An ERROR response code results if this command is issued
while the modem is on-hook.
+FTM=n Transmit Data. +FTM=n causes the modem to
transmit data using the modulation defined below. An ERROR response code
results if this command is issued
while the modem is on-hook.
Parameters:
Command options:
+FTM=3 V.21 ch.2 300 bps
+FTM=24 V.27 ter 2400 bps
+FTM=48 V.27 ter 4800 bps
+FTM=72 V.29 7200 bps
+FTM=96 V.29 9600 bps
+FTM=73 V.17 7200 bps long
+FTM=74 V.17 7200 bps short
+FTM=96 V.29 9600 bps
+FTM=97 V.17 9600 bps long
+FTM=98
V.17 9600 bps short
+FTM=121 V.17 12000 bps long
+FTM=122 V.17 12000 bps short
+FTM=145 V.17 14400 bps long
+FTM=146 V.17 14400 bps short
+FRM=n Receive Data. Causes the modem to enter the
receive mode using the modulation defined below. An ERROR response code results
if this command is issued while
the modem is on-hook.
Parameters: see Command options
Command options:
+FRM=3 V.21 ch.2 300 bps
+FRM=24 V.27 ter 2400 bps
+FRM=48
V.27 ter 4800 bps
+FRM=72 V.29 7200 bps
+FRM=73 V.17 7200 bps long
+FRM=74 V.17 7200 bps short
+FRM=96 V.29 9600 bps
+FRM=97 V.17 9600 bps long
+FRM=98 V.17 9600 bps short
+FRM=121 V.17 12000 bps long
+FRM=122 V.17 12000 bps short
+FRM=145 V.17 14400 bps long
+FRM=146 V.17 14400 bps short
+FTH=n Transmit Data with HDLC Framing. Causes the modem to transmit data using HDLC
protocol and the modulation defined below. An ERROR response code results if
this command is issued while the modem is on- hook.
Parameters: See Command options.
Command options:
+FTH=3 V.21 ch. 2 300 bps
+FTH=24 V.27 ter 2400 bps
+FTH=48 V.27 ter 4800 bps
+FTH=72 V.29 7200 bps
+FTH=73 V.17 7200 bps long
+FTH=74 V.17 7200 bps short
+FTH=96 V.29 9600 bps
+FTH=97 V.17 9600 bps long
+FTH=98 V.17 9600 bps short
+FTH=121 V.17 12000 bps long
+FTH=122 V.17 12000 bps short
+FTH=145 V.17 14400 bps long
+FTH=146 V.17 14400 bps short
+FRH=n Receive Data with HDLC Framing. Causes
the modem to receive frames using HDLC protocol and the modulation defined below.
An ERROR response code results if this command is issued while the modem is
on-hook.
Parameters: See Command options:
Command options:
+FRH=3 V.21 ch.2 300 bps
+FRH=24 V.27 ter 2400 bps
+FRH=48
V.27 ter 4800 bps
+FRH=72 V.29 7200 bps
+FRH=73 V.17 7200 bps long
+FRH=74 V.17 7200 bps short
+FRH=96 V.29 9600 bps
+FRH=97 V.17 9600 bps long
+FRH=98 V.17 9600 bps short
+FRH=121 V.17 12000 bps long
+FRH=122 V.17 12000 bps short
+FRH=145 V.17 14400 bps long
+FRH=146 V.17 14400 bps short
Fax Class 2 Commands
Command Function
Service Class ID
+FCLASS= Service Class
Class 2
Action Commands
D Originate a Call
A Answer a Call
+FDT= Data Transmission
+FET=N Transmit Page Punctuation
+FDR Begin / Continue Phase C Receive Data
+FK Session Termination
Class 2
DCE Responses
+FCON Facsimile Connection Response
+FDCS: Report Current Session
+FDIS: Report Remote Identification
+FCFR Indicate Confirmation or Receive
+FTSI: Report the Transmit Station ID
+FCSI: Report the Called Station ID
+FPTS: Page Transfer Status
+FET: Post Page Message Response
+FHNG Call Termination with Status
+FMFR? Identify Manufacture
+FMDL? Identify Model
+FREV? Identify Revision
+FDCC= DCE Capabilities Parameters
+FDIS= Current Session Parameters
+FDCS= Current Session Results
+FLID= Local ID string
+FCR Capability to Receive
+FPTS= Page Transfer Status
+FCR? Capability to Receive
+FAA Adaptive Answer
+FBUF? Buffer Size (Read Only)
+FPHCTO Phase C Time Out
+FAXERR Fax Error Value
+FBOR Phase C Data Bit Order
d is
issued while the modem is on-hook.