18
AT COMMANDS
Bold text indicates Async Dial factory defaults.
AT Attention Command Prefix/Autobaud
Rate. Indicates a command string has
started and determines the DTE’s data
rate and parity.
A/ Repeat Last Command. Re-executes
last command string. (Not to be
preceded with AT or followed by pressing
Enter.)
A Answer Mode. Goes off-hook and
attempts to establish a connection
without waiting for a ring.
B

n ITU-T/Bell Mode

B0 V.21 or V.22 (300 or 1200 bps).
B1 Bell 103 or 212A (300 or 1200 bps).
D
n
Dial. Dials the telephone number entered
for

n.

DS=
n
Dial Stored Number. Dials the number
stored in location
n
(1–10).

En Command Character Echo

E0 Disables echo to the DTE.
E1 Enables echo to the DTE.
H0 Modem goes on-hook.
H1 Modem goes off-hook.
I0 Displays product code–144.
I1 Displays 3-digit firmware revision
number.
I2 Performs an EPROM check.
I3 Displays modem’s serial number.
I4 Displays modem’s model number.
I5 Displays part number of circuit card.
I6 Displays firmware release number.
I9 (same as I1)
I10=
n
Changes value of product code (0=144,
1=240, 2=480, 3=960, 4=120).
I11 Firmware checksum.
I19 Displays entire firmware revision number.

Ln Speaker Volume

L0,L1 Selects low volume.
L2 Selects medium volume.
L3 Selects high volume.

Mn Speaker ON/Off Control

M0 Speaker always Off.
M1 Speaker ON until carrier signal
becomes active.
M2 Speaker always ON.
O Returns modem to Data mode from
online Command mode.
P Enables Pulse Dial mode.
AT COMMANDS (continued)

Qn Result Codes

Q0 Enables result codes. Refer to

Result

Codes

section.
Q1 Disables result codes.
Q2 Enables originate modem to send result
codes to the DTE. Required for most
UNIX applications.
S
r
? Displays value of S-Register (where

r

is
the register number).
S

r=n

Change S-Register. Changes the
contents of the S-Register (where
r
is the
register number and
n
is the assigned
value).
T Enables Tone Dial mode.

Vn Result Code Format

V0 Displays as digits (Numbers 1).
V1 Displays as text.
V2 Displays as digits (Numbers 2).

Xn Extended Result Codes; Dial Tone

Detect; Busy Tone Detect

X0 Disables extended result codes 5–16,
dial tone detect, and busy tone.
X1 Enables extended result codes 5–16,
disables dial tone detect and busy tone
detect. Refer to
Result Codes
section.
X2 Enables extended result codes 5–16, dial
tone detect, and disables busy tone
detect.
X3 Enables extended result codes 5–16,
disables dial tone detect and enables
busy tone detect. Refer to
Result Codes
section.
X4 Enables extended result codes 5–16,
dial tone detect, and busy tone detect.
Refer to
Result Codes
section.
X5 Adds EC suffix to extended result codes
(20–27) if error control is used, enables
dial tone detect and busy tone detect.
X6 Adds either V.42 or MNP suffix to
extended result codes (20–27) if data
compression is used, enables dial tone
detect, and busy tone detect.
X7 DTE rate appears in CONNECT
message instead of line rate, enables dial
tone detect and busy tone detect. Refer
to
Result Codes
section.

Yn Long Space Disconnect

Y0 Disable.
Y1 Enable.

Zn Reset and Load Active

Z0 Loads contents of Active (Saved) into
Active (Operating).
Z1 Loads contents of Customer 1 into Active
(Operating).
Z2 Loads contents of Customer 2 into Active
(Operating).