Modem - Hayes-AT - Commands - Functions
The Hayes-AT command set is not a definite standard, however most
modems will follow near all of the below specified AT-commands.
If the origin Modem-Manual is available, I would highly recommend to use the
origin setup instructions, rather than use the below tables.
When entering an AT-commandstring do not mix UPPER-CASE and lower-case letters.
(Sample: use AT&F -or- at&f and not aT&f )
Modem Commands - Functions
Command
CMD-n
Modem Function/Option
A
Manual Answer mode (when modem has not received
an incoming call) modem forced to Off Hook
A/
Re-execute last command once (Re-dial)
A>
Repeat last command (10x) continuously
Any key
Terminate current connection attempt,
and exit Repeat mode - go Off Hook
AT
Attention: must precede all other commands,
except A/, A>, and +++
Bn
U.S./(CCITT) ITU-T Handshake options
B0
ITU-T-V.25 (CCITT) answer sequence
B1
Reserved
Cn
Transmitter On/Off
C0
Transmitter Off
C1
Transmitter On-Default
Dn
Dial number n and go into originate mode
P
Pulse dial - Default
T
Touch-Tone dial (DTMF-tone)
, (Comma)
Pause for 2 seconds
;
Return to AT-cmd state after dialing
"...
Dial the letters that follow
!
Flash switch-hook to transfer call
/ (slash)
Delayed (125ms) dial operation
W
Wait for 2nd dial tone (if X3 or higher is set)
@
Wait for an answer (if X3 or higher is set)
R
Connect - use (Reverse) frequencies
S
Dial stored number
DL
Dial the last-dialed number
D$
Online Help - show dial commands
DSn
Dial number stored in NVRAM at position n (0-3)
En
Command mode local echo, not applicable after
a connection has been made
E0
Echo Off
E1
Echo On - Default
Fn
Local echo On/Off when a connection has been made
F0
Echo On (Half duplex)
F1
Echo Off (Full duplex) - Default
Hn
On/Off hook control
H0
Hang up (go on hook) - Default
H1
Go off hook
In
Inquiry
I0
Return modem product code/version
I1
Return memory (ROM) checksum
I2
Run memory (RAM) test
I3
Returns product-type or call duration/real time
I4
Return current active modem settings
I5
Return NVRAM settings
I6
Return link diagnostics
I7
Return product (Flash) configuration
I9
Return Plug-and-Play (PnP) information
I11
Return connection statistic
Kn
Modem clock operation
K0
ATI3 displays call duration - Default
K1
ATI3 displays real time, set with ATI3=HH:MM:
Ln
Loudness of speaker volume
L0
Low
L1
Low
L2
Medium
L3
High
Mn
Monitor (speaker) control
M0
Speaker always set to Off
M1
Speaker On until carrier is established - Default
M2
Speaker always On
M3
Speaker On after last digit dialed out,
Off at start (connect) carrier detected
On
Return on-line after command execution
O0
Return on-line, normal
O1
Return on-line, start retrain
P
Pulse dial
Qn
Result codes display
Q0
Result codes displayed
Q1
Result codes suppressed (quiet mode)
Q2
Result codes during dial out only
Q3
Result codes only in answering mode
Sr=n
Set Register commands: r is any S-register,
n must be a decimal number between 0 and 255.
Sr.b=n
Set bit.b of register r to n (0=OFF or 1=On)
Sn?
Query register n
T
Tone dial
Vn
Verbal/Numeric result codes
V0
show numeric result codes
V1
show verbal (text) result codes
Xn
Result code options - Default = X4
Yn
Load working RAM at PWR-On/reset with
configuration (data) from
Y0
Load NVRAM-profile 0 - Factory default 0
Y1
Load NVRAM-profile 0 - Factory default 1
Y2
Load user profile - &F0
Y3
Hardware profile - Factory &F1
Y4
Software profile - Factory &F2
Zn
Modem - reset control
Z0
Reset Modem - use Y-command NVRAM profile
Z1
Reset Modem - use NVRAM Profile-0
Z2
Reset Modem - use NVRAM Profile-1
Z3
Reset Modem - use Factory Profile-0
Z4
Reset Modem - use Factory Profile-1
Z5
Reset Modem - use Factory Profile-2
+++
Escape code sequence, preceded and followed by at
least one second of no data transmission.
>
Repeat command continuosly or up to 10 dial
attempts Canceled by pressing any key
$
Online Help - Basic command summary
&$
Online Help - & command summary
%$
Online Help - % command summary
D$
Online Help - Dial command summary
S$
Online Help - S-Register summary
<Ctrl>S
Stop/restart display of HELP screens
<Ctrl>C
Cancel display of HELP screens
<Ctrl>K
Cancel display of HELP screens
&An
ARQ result codes 14-17, 19
&A0
Supress ARQ result codes
&A1
Display ARQ result codes
&A2
Display HST and V.32 result codes
&A3
Display protocol result codes LAMP/MNP/NONE
- Default
&Bn
Data Rate, terminal-to-modem (DTE/DCE)
&B0
DTE rate follows connection rate - Default
&B1
Fixed DTE rate - Default
&B2
Fixed DTE rate in ARQ mode, variable DTE rate
in non-ARQ mode.
&Cn
Carrier Detect (CD) operations
&C0
CD override
&C1
Normal CD operations - Default
&Dn
Data Terminal Ready (DTR) operations
&D0
DTR override
&D1
Reserved
&D2
Normal DTR Operation - Default
&Fn
Load Factory default settings into working RAM
&F0
Load user (saved) settings into working RAM
&F1
Load hardware-control profile
&F2
Load software-control profile
&Gn
Guard tone
&G0
No guard tone, U.S. and Canada - Default
&G1
550Hz-Guard tone, some European countries
&G2
1800Hz-Guard tone, U.K. requires B0-setting
&Hn
Transmit Data flow control
&H0
Flow control disabled - Default
&H1
Hardware (CTS) flow control
&H2
Software (XON/XOFF) flow control - Printer
&H3
Hardware and software control
&In
Received Data software flow control
&I0
Flow control disabled - Default
&I1
XON/XOFF to local modem and remote computer
&I2
XON/XOFF to local modem only
&I3
Host mode, Hewlett Packard protocol
&I4
Terminal mode, Hewlett Packard protocol
&I5
ARQ mode same as &I2, non-ARQ mode,
look for incoming XON/XOFF
&Jn
Telephone jack selection
&J0
RJ-11, RJ-41S, RJ-45S
&J1
RJ-1, RJ-12, RJ-13
&Kn
Data Compression
&K0
Disabled
&K1
Auto enable/disable - Default
&K2
Compression enabled
&K3
MNP5 - compression disabled
&Ln
Switched/Leased line operation
&L0
Normal phone line (switched) - Default
&L1
Leased line
&Mn
Error Control/Synchronous Options => 1200 Bps
&M0
Normal mode, no error (ARQ) control
&M1
Synchronous mode
&M2
Synchronous mode 2 stored number dialing
&M3
Synchronous mode 2 manual dialing
&M4
Normal/ARQ - Default
&M5
ARQ mode hang-up if ARQ connection cannot be made
&Nn
Data Rate, data link (DCE/DCE)
&N0
Variabl Rate operations - Default
&N1
300 bps
&N2
1200 bps
&N3
2400 bps
&N4
4800 bps
&N5
7200 bps
&N6
9600 bps
&N7
12.000 bps
&N8
14.400 bps
&N9
16.800 bps
&N10
19.200 bps
&N11
21.600 bps
&N12
24.000 bps
&N13
26.400 bps
&N14
28.800 bps
&N15
31.200 bps
&N16
33.600 bps
&Pn
Pulse dial make/break ratio
&P0
North America 39%-61% - Default
&P1
British Commonwealth 33%-67%
&Rn
Received Data hardware (RTS) flow control
&R0
CTS follow RTS
&R1
Ignore RTS
&R2
Pass received data on RTS high, used Pass received
data on RTS high - Default
&Sn
Data Set Ready (DSR) override
&S0
DSR override (always on) - Default
&S1
Modem controls DSR
&Tn
Modem Testing
&T0
End Testing
&T1
Analog loopback (AL-Test)
&T2
Reserved
&T3
Digital loopback (DL-Test)
&T4
Grant remote digital loopback (RDL-Test)
&T5
Deny remote digital loopback
&T6
Start remote digital loopback
&T7
Start digital loopback with self-test
&T8
Start analog loopback with self-test
&Wn
Save current working RAM settings
&W0
Save RAM settings to NVRAM profile 0 (Y0)
&W1
Save RAM settings to NVRAM profile 1 (Y1)
&Xn
Synchronous timing source
&X0
Use modem X-mit clock
&X1
Use terminal X-mit clock
&X2
Use modem receiver clock
&Yn
Break handling. Destructive breaks clear
the buffer, expedited breaks are sent immediately
to remote system.
&Y0
Destructive, don't send break
&Y1
Destructive expedited - Default
&Y2
Non-destructive, expedited
&Y3
Reserved
&Zn=L
Store last-dialed phone number in NVRAM at pos n
&Zn=s
Write phone number(s) to NVRAM at pos n (0-3),
36 characters maximum
&Zn?
Display phone number in NVRAM at pos. n (n=0-3)
%Rn
Remote access to Rack Controller Unit (RCU)
%R0
Disabled
%R1
Enabled
%T
Enable Touch Tone recognition
S-Register Settings - Functions
S-Register
Value
Modem Function/Option
S1
Count and stores numer of incoming rings
S2
Define escape code character - Default = + (43)
S3
Define ASCII (CR) carrige return (13)
S4
Define ASCII (LF) line feed (10)
S5
Define ASCII (BS) Backspace (8)
S6
Number of seconds wait before dial (2)
S7
Number of seconds wait for carrier (30)
S8
Duration (sec) for pause (,) option in Dial
command and pause between command re-executions
for Repeat (>) command.
S9
Duration (.1sec units) of remote carrier signal
before recognition. (6)
S10
Duration (.1sec units) modem waits after loss of
carrier signal before go on hook. (7)
S11
Duration and spacing (ms) of dialed Touch-Tones
(DTMD-tone) (70)
S12
Guard time (in .02 sec units) for escape code
sequence (+++) (50)
S13
Bit-mapped register (0)
1
Reset when DTR drops
2
Auto answer in originate mode
4
Disable result code pause
8
DS0 on DTR low-to-high
16
DS0 on power up, ATZ
32
Disable HST modulation
64
Disable MNP level 3
128
Watchdog hardware reset
S15
Bit-mapped register (0)
1
Disable high-frequency equalization
2
Disable on-line fallback
4
Force 300-bps back channel
8
Set non-ARQ x-mit buffer to 128 bytes
16
Disable MNP level 4
32
Set DEL as Backspace key
64
Unusual MNP incompatibility
128
Custom applications only
S16
Bit-mapped register (0)
1
Analog loopback
2
Dial test
4
Test pattern
8
Initiate remote digital loopback
16
Reserved
32
Reserved
64
Reserved
128
Reserved
S18
&Tn Test timer, disabled when set to 0 (0)
S19
Set inactivity timer in minutes (0)
S21
Length of Break, DCE to DTE, in 10ms units
S22
Define ASCII XON (17)
S23
Define ASCII XOFF (19)
S24
Duration (20ms units) of pulsed DSR when modem
is set to &S2 or &S3 (150)
S25
Delay to DTR in 10ms units (5)
S26
Duration (10ms units) of delay between RTS and
CTS, synchronous mode (1)
S27
Bit-mapped register (0)
1
Enable V.21 modulation 300 bps
2
Enable unencoded V.32 moulation
4
Disable V.32 modulation
8
Disable 2100 Hz answer tone
16
Disable MNP handshake
32
Disable V.42 Dtect phase
64
Reserved
128
Unusual software in compatibility
S28
Duration (.1sec units) of V.21/23 handshake delay
S32
Voice-Data switch options (1)
0
Disabled
1
Go off hook in originate mode
2
Go off hook in answer mode
3
Redial last dialed number
4
Dial number stored at position 0
5
Auto answer toggle On/Off
6
Reset modem
7
Initiate remote digital loopback
S34
Bit-mapped register (0)
1
Disable V.32bis
2
Disable enhanced V.32 mode
4
Disable quick V.32 retrain
8
Enable V.32 modulation
16
Change MR LED to DSR
32
Enable MI/MIC
64
Reserved
128
Reserved
S38
Duration(sec) before disconnect when DTR drops
during an ARQ call (0)
Please see the LEGAL - Trademark notice.
Feel free - send a for any BUG on this page found - Thank you.