
TECHNICAL QUICK REFERENCE
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This section includes information about:
• Lights (external modems only)................................................................2
• Typing Commands.................................................................................4
• Basic Data Commands..........................................................................5
• Extended Data Commands...................................................................13
• DIP Switches......................................................................................20
• S-Registers.........................................................................................22
• Fax Commands...................................................................................33
• The Serial Interface (cable information)................................................37

TECHNICAL QUICK REFERENCE
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Lights (External Modems Only)
Front-of-the-Case Lights (on All Non-Voice Externals and Some Voice Externals)
Symbol Meaning Status
AA............Auto Answer Answer mode: ON when register S0 is set to 1 or higher (Auto Answer),
and when answering a call; OFF when modem originates a call. Light
flashes when there is an incoming call.
CD.............Carrier Detect ON if modem receives a valid data signal (carrier) from a remote modem,
indicating that data transmission is possible. Always ON if CD override is
ON (&C0).
RD.............Received Data Flashes when modem sends result codes or passes received data bits from
remote.
SD..............Send Data Flashes when computer sends a data bit to modem.
TR..............Data Terminal Ready ON if modem receives a DTR signal from computer. Always ON (modem
ignores DTR) if the DTR override is ON (&D0).
CS..............Clear to Send ON until modem lowers CTS when Transmit Data hardware flow control is
enabled (&H1, &H3).
ARQ/ Error Control/
FAX..........Fax Operations Data Mode: Automatic Repeat Request. ON if modem is set to &M4 or &M5
and successfully establishes an error control connection. Flashes when
modem retransmits data to remote modem. Fax Mode: Flashes to indicate fax
mode.

TECHNICAL QUICK REFERENCE
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Top-of-the-Case Lights (on Some Voice Externals)
Light What It Means When Lit
POWER................The modem is turned on.
SEND...................The computer is sending a data bit to the modem.
RECEIVE .............The modem is sending result codes or passing received data bits from the remote.
ONLINE...............The modem is online. (NOTE: This light blinks when the mute feature is being
used.)

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Typing Commands
• Type commands in either upper or lower case, not a combination. Use the
Backspace key to delete errors. (You cannot delete the original AT command since
it is stored in the modem buffer.)
• If a command has numeric options and you don’t include a number, zero is
assumed. For example, if you type ATB, the command ATB0 is assumed.
• Every command except A/, +++, and A> must begin with the AT prefix and be entered
by pressing ENTER.
• The maximum command length is 58 characters. The modem doesn’t count the AT prefix,
carriage returns, or spaces.
NOTE: All defaults are based on the &F1Hardware Flow Control template
loaded in NVRAM when the modem is shipped. Defaults are listed in italics.

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Basic Data Commands
<control key>S
Stop or restart help screens.
<control key>C
or
<control key>K
Stop help screens.
$ Use in conjunction with D, S,
or & commands (or just AT)
to display a basic command
list; online help.
A Manual Answer: goes off hook
in answer mode. Pressing any
key aborts the operations.
A/ Re-executes the last issued
command. Used mainly to
redial. Does not require the
AT prefix or a Carriage
Return.
A> Re-executes the last issued
command continuously, until
the user intervenes or the
command is executed. forever.
Does not require the
AT prefix or a Carriage
Return.
Any key Aborts off-hook dial/answer
operation and hangs up.
AT Required command prefix, except
with A/, +++, and A>. Use alone to
test for OK result code.

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Bn U.S./ITU-T answer
sequence.
B0 ITU-T answer
sequence
B1 U.S. answer tone
Dn Dials the specified phone
number. Includes the
following:
0-9 Numeric digits
#, * Extended touch-tone
pad tones
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.

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Dn (cont.)
@ Dials, waits for quiet answer,
and continues (X3 or higher).
$ Displays a list of Dial
commands.
En Sets local echo.
E0 Echo OFF
E1 Modem displays
keyboard commands
Fn Sets online local echo of
transmitted data ON/OFF.
F0 Local echo ON.
Modem sends a copy
of data it sends to the
remote system to your
screen.
F1 Local echo OFF. Receiving
system may send a remote
echo of data it receives.
Hn Controls ON/OFF hook.
H0 Hangs up (goes on hook).
H1 Goes off hook.
In Displays the following information.
I0 Four-digit product code
I1 Results of ROM checksum
I2 Results of RAM checksum
I3 Product type
I4 Current modem settings
I5 Nonvolatile memory
(NVRAM) settings
I6 Link diagnostics
I7 Product configuration
I9 Plug and Play information
I11 Extended link diagnostics

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Ln Controls speaker volume
(internals only).
L0 Low volume
L1 Low volume
L2 Medium volume
L3 High volume
Mn Operates speaker.
M0 Speaker always OFF.
M1 Speaker ON until
CONNECT.
M2 Speaker always ON.
M3 Speaker ON after dial,
until CONNECT.
On Returns online.
O0 Returns online.
O1 Returns online and
retrains.
P Sets pulse dial (for phone
lines that don’t support
touch-tone dialing).
Qn Displays/suppresses result
codes.
Q0 Displays result codes.
Q1 Quiet mode; no result
codes.
Q2 Displays result codes
only in Originate
mode.

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Sr.b=nSets bit .b of register r to n
(0/OFF or 1/ON).
Sr=n Sets register r to n.
Sr? Displays contents of
S-Register r.
S$ Displays a list of the S-
Registers.
T Sets tone dial.
Vn Displays verbal/numeric
result codes.
V0 Numeric codes
V1 Verbal codes

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Xn Sets result code displayed. Default is X4.
Result Codes X0 X1 X2 X3 X4
0/OK • • • • •
1/CONNECT • • • • •
2/RING • • • • •
3/NO CARRIER • • • • •
4/ERROR • • • • •
5/CONNECT 1200 • • • •
6/NO DIAL TONE • •
7/BUSY • •
8/NO ANSWER* • •
9/Reserved
10/CONNECT 2400 • • • •
11/RINGING •
13/CONNECT 9600 • • • •
18/CONNECT 4800 • • • •
20/CONNECT 7200 • • • •
21/CONNECT 12000 • • • •
25/CONNECT 14400 • • • •
43/CONNECT 16800 • • • •
85/CONNECT 19200 • • • •
91/CONNECT 21600 • • • •
99/CONNECT 24000 • • • •
103/CONNECT 26400 • • • •
107/CONNECT 28800 • • • •
151/CONNECT 31200 • • • •
155/CONNECT 33600 • • • •

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Xn Result Codes (cont.) X0 X1 X2 X3 X4
256/CONNECT 28000 • • • •
260/CONNECT 29333 • • • •
264/CONNECT 30666 • • • •
268/CONNECT 32000 • • • •
180/CONNECT 33333 • • • •
272/CONNECT 34666 • • • •
276/CONNECT 36000 • • • •
184/CONNECT 37333 • • • •
280/CONNECT 38666 • • • •
284/CONNECT 40000 • • • •
188/CONNECT 41333 • • • •
192/CONNECT 42666 • • • •
196/CONNECT 44000 • • • •
200/CONNECT 45333 • • • •
204/CONNECT 46666 • • • •
208/CONNECT 48000 • • • •
212/CONNECT 49333 • • • •
216/CONNECT 50666 • • • •
220/CONNECT 52000 • • • •
224/CONNECT 53333 • • • •
228/CONNECT 54666 • • • •
232/CONNECT 56000 • • • •
236/CONNECT 57333 • • • •
Adaptive Dialing • • •
Wait for 2nd Dial Tone (W) • •
Wait for Answer (@) • •
Fast Dial • •
*Requires @ in dial string; replaces NO CARRIER

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Yn Selects power-on/reset
default configuration.
Y0 Use profile 0 setting
in NVRAM
Y1 Use profile 1 setting in
NVRAM
Y2 Use factory
configuration 0.
Y3 Use factory
configuration 1.
Y4 Use factory
configuration 2
Z Resets modem.
Z0 Resets modem to
NVRAM profile
selected by Y
command or dip 7.
Z1 Resets modem to
NVRAM profile 0
Z2 Resets modem to
NVRAM profile 1
Z3 Resets modem to
factory default profile
0 (&F0)
Z4 Resets modem to
factory default profile
1 (&F1)
Z5 Resets modem to
factory default profile
2 (&F2)