This Pocket Guide is intended to summarize all commands, responses, register
values, RS232 pin interface spec information that an experienced user may
need to operate a Multi-Tech Modem. The definition and use of the commands
is general in nature and not model specific.
For more in-depth information, refer to the Modem Reference Manual or your
Modem Owner's Manual.
This Pocket Guide provides:
Commands
∙ AT (Basic) ∙ AT (Extended)
∙ Password ∙ Callback Security
∙ Error Correction ∙ Leased/Dial-Up
∙ Fax (+F) ∙ Voice (>)
∙ V.25bis ∙ Hidden
∙ DOS
S-Register
∙ Defining ∙ Counting
∙ Bit Mapped ∙ Remote Configuration
Result Codes
∙ Terse ∙ Verbose
∙ Connect ∙ Speed
∙ Reliable Mode ∙ Data Compression
DIP-Switches
∙ Async Operation ∙ Sync Operation
RS232C/V.24/V.28 Specifications
∙ Pin Assignment ∙ Multi-Tech Designation
∙ EIA Circuit ∙ Signal Source
∙ Circuit Function
Notes
Basic AT Commands
Function Command Description
AT Attention Code that precedes all command
lines except A/, A:, and Escape Codes.
DIAL Ds Dial a telephone number "s", where s may
include up to 60 digits or T,P,R, comma and
; characters.
A: Continuous redial of last number until
answered.
MODIFY $Dn $D0 disables DTR Dialing.
DIAL $D1 enables DTR Dialing.
P Pulse dials number following P.
&Pn &P0 sets 60-40 pulse ratio.
&P1 sets 67-33 pulse ratio.
T Tone dials number following T.
, Automatic Pauses in Dialing
Yn Y0 disables sending or responding to long
space "break".
Y1 enables sending or responding to long
space "break".
W Wait for new dial tone.
; Return to command mode after dialing
Rn R0 means modem will not reverse modes.
R1 means modem will reverse modes.
! Causes modem to flash On-Hook
@ Causes modem to wait for ringback, then 5
seconds of silence, before processing next
part of command.
MODE &Mn &M0 enables Async when on-line.
SELECT &M1 enables Sync when on-line.
&Xn &X0 selects internal clock (enables
DIP-Switch #11 to select clock).
&X1 selects external clock (overrides DOWN
position of DIP-Switch 11).
&X2 selects slave clock.
$Vn $V0 disables V.25bis mode.
$V1 selects V.25bis mode.
$V2 allows one V.25bis command in AT mode
without leaving AT mode (V.25bis command
follows $V2 command).
STORE DsNd Store Phone Number. To store,
PHONE phone number "s" is entered and
NUMBERS followed by N and then directory number "d".
Nd Dial Stored Number "d". (Do not include the
letter d in this command).
Function Command Description
STORE NdNe Number Linking. If first number
PHONE dialed is busy, another stored
NUMBERS number may be automatically dialed.
L List all stored telephone numbers stored in
memory.
RESET Z All configuration parameters are
FACTORY reset to default values.
DEFAULTS &F Loads factory defaults from ROM.
&Fn &F8 determines function of &F. If
&F8 is entered and subsequent &F,
modem reads factory defaults regardless of
what is stored in RAM.
&F9 determines function of &F. If &F9 is
entered and subsequent &F, modem reads
parameters and values in RAM as defaults.
STORE &Wn &W0 stores current parameters in
MODEM non-volatile RAM and loads these
CONFIGURATION for future sessions instead of
reading factory ROM defaults,
unless &F command is used.
&W1 causes modem not to store parameters.
COMMAND En E0 does not echo command mode
RESPONSES characters.
E1 echoes command mode characters.
Qn Q0 means result codes are sent
Q1 means result codes are suppressed (quiet).
Q1 means Dumb Answer Mode.
&Qn &Q0 selects Multi-Tech Result Codes.
&Q1 selects standard AT Result Codes.
Vn V0 means result codes displayed as digits
(terse response).
V1 means result codes displayed as words
(verbose response).
Xn X0 selects basic Result Codes (w/o CONNECT
1200, CONNECT 2400)
X1 selects extended Result Codes (w/ CONNECT
1200, CONNECT 2400).
X2 selects standard AT command response with
NO DIAL TONE.
X3 selects standard AT command response with
BUSY.
X4 selects standard AT command response with
NO DIAL TONE and BUSY.
Function Command Description
MISCELLANEOUS A Answer call, even if no ring present.
COMMANDS
Bn B0 selects CCITT tones.
B1 selects Bell tones.
$Hn $H1 brings up Help Screen #1.
$H2 brings up Help Screen #2.
$H3 brings up Help Screen #3.
Hn H0 means Hang Up (go on hook)
H1 means Go Off Hook
In I0 requests modem ID number.
I1 requests firmware revision number.
Ln L5 list current operating parameters.
L6 list S-Register values.
L7 list additional configuration parameters.
Mn M0 means speaker is always Off.
M1 means speaker is On until carrier is
detected.
M2 means speaker is always On.
M3 means speaker is On during dialing and
Off during handshaking.
S Sr=n sets value of S-Register "r" to value
of "n". "n" entered in decimal format. All
S-Registers defined later in Pocket Guide.
Sr? Reads value of S-Register "r" and
displays 3-digit decimal value. All
S-Registers defined later in Pocket Guide.
ON-LINE/ O Exit command mode and go on-line.
OFF-LINE
+++AT Escape code which brings modem into command
mode while remaining On-line.
%En %E0 means modem will not
perform Escape Sequence.
%E1 means modem responds to +++ AT <CR>
Escape Method.
%E2 means modem responds to the Break
Method.
%E3 means modem responds to either +++ or
Break Method.
%E4 disables OK response to +++ Escape
Method
%E5 enables OK response to +++ Escape
Method
%E1,%E5 enables +++ Escape Method and OK
response to +++ Escape Method
%E3,%E5 enables either Break or +++ Escape
Method and OK response to +++ Escape Method
Function Command Description
CONTROL &Cn &C0 forces Carrier Detect On.
RS232C &C1 lets Carrier Detect act
INTERFACE normally.
&C2 lets Carrier Detect drop at S24 time
on disconnect.
&C4 resets modem when carrier detect drops.
&Dn &D0 enables modem to ignore DTR
&D1 enables modem to hang-up with loss of
DTR.
&D2 lets modem react to DTR normally.
&D3 causes modem to reset to modem default
parameters.
&RFn &RF0 selects CTS to follow RTS.
&RF1 selects CTS to act independently.
&SFn &SF0 selects DSR to follow CD.
&SF1 selects DSR independently
TEST Un U0 places modem in analog loop originate
mode.
U1 places modem in analog loop answer mode.
U2 places modem in remote digital loopback
mode.
U3 places modem in local digital loopback
mode.
&Tn &T4 enables response to request for remote
digital loopback.
&T5 disables response to request for remote
digital loopback.
Advanced AT Commands
Function Command Description
SPECIAL $SPn $SP0 disables spoofing.
FEATURE $SP1 enables spoofing.
$EBn $EB0 enables 10-bit asynchronous format.
$EB1 enables 11-bit asynchronous format.
&An &A0 disables Answerback feature.
&A1 enables Answerback
PERFORMANCE #An #A0 means Auto-Speed Detection
CONDITIONING from 14,400 bps to 12,000 bps to
9600bps to 4800 bps to 2400 bps to
1200 bps to 300 bps.
#A1 means 14,400 bps Auto-Speed Detection.
#A2 means Auto-Speed Detection from 14,400
bps to 9600 bps to 4800 bps only.
#A3 means Auto-Speed Detection
from 2400 bps to 1200 bps to 300 bps only.
&Bn &B0 means normal transmit buffer size.
&B1 means reduced transmit buffer size.
#Fn #F0 means no fallback when on-line.
#F1 enables fallback from 14,400 bps to
4800 bps when on-line.
#F2 enables fallback to 4800 bps from
14,400 bps with fall forward if phone line
improves.
&Gn &G0 turns Off CCITT guard tones.
&G1 turns On CCITT 550 Hz guard tones.
&G2 turns On CCITT 1800 Hz guard tones.
#Tn #T0 turns Off Trellis Coded Modulation.
#T1 turns On Trellis Coded Modulation.
$Fn $F0 means do not fall back to normal
connect if CR received.
$F1 means fall back to normal connect if
CR received.
Password Commands
Command Description
#Ixxxxxxxxxx Login Password is any keyboard characters (x) (upper/
lower case sensitive), minimum 6 and maximum 10
characters. The default Login Password is MULTI-TECH.
#Syyyyyyyyyy Set-up Password is any keyboard characters (y) (upper
/lower case sensitive), minimum 6 and maximum 10
characters. The default Set-up Password is
MODEMSETUP.
Callback Security/Remote Configuration Commands
Command Description
#DBn #DB0 disables Callback Security and answering Yes to the
prompt turns off Callback Security and erases stored phone
numbers and passwords. Answering No to the prompt aborts the
command.
#DB1 activates remote and local password security.
#DB2 activates remote password security.
CBNyyxxxxxx Callback password with xxxxxx being callback password and yy
being the memory location. Callback password xxxxxx must
start with a non-numeric character and upper/lower case
sensitive. Callback password xxxxxx must be a minimum of 6
and maximum of 10 characters. yy memory locations are from 0
to 29.
+ - Dxxxxxx???Nxx Callback Phone Numbers xxxxxx with the + preceding
the phone number indicating the callback modem phone
number for the corresponding password at the same
memory location. The (-) preceding the phone number
enables direct entry when the caller uses the correct
password without the callback modem having to return
the call. The ??? entry at the end of the phone
number represents an extension added to the main
phone number. The Nxx is the memory location of the
callback phone number and password.
#Pn Parity of the prompt messages sent by the callback modem.
#P0 is no parity
#P1 is odd parity
#P2 is even parity
#RCBNxx Erases the callback password stored at memory location xx.
Memory locations are 0 to 29.
#RDNxx Erases the callback phone number stored at memory location
xx. Memory locations are 0 to 29.
Error Correction and Speed Conversion Commands
Function Command Description
CONFIGURE $An $A0 discards data during auto
ERROR - reliable time period.
CORRECTION $A1 buffers data during auto-reliable time
period
&BSn &BS0 means maximum transmit block size of
64 characters.
&BS1 means maximum transmit block size of
256 characters.
&En &E0 Normal Mode
&E1 V.42 Auto-Reliable Mode
&E2 V.42 Reliable Mode
$E $E0 is no error correction at 300 bps
$E1 enables &E0-2 connections at 300 bps.
#Ln #L0 means modem negotiate V.42
Mode during handshake.
#L1 means MNP On and LAPM Off
#L2 means LAPM On and MNP Off
#L3 means no detection phase but go
directly to LAPM.
$Rn $R0 enables disconnect after 12 retransmits.
$R1 means modem will not disconnect on any
number of retransmits.
CONFIGURE &En &E3 is no modem initiated flow
FLOW control.
CONTROL &E4 is CTS modem initiated hardware flow
control.
&E5 Xon/Xoff modem-initiated flow control
&E6 is Xon/Xoff not pass-through
&E7 Xon/Xoff with Pass-Through
&E8 Enq/Ack pacing Off
&E9 Enq/Ack pacing On
&E10 normal mode flow control Off
&E11 normal mode flow control On
&E12 pacing Off
&E13 pacing On
CONFIGURE &En &E14 data compression disabled
DATA &E15 data compression enabled
COMPRESSION
Function Command Description
CONFIGURE $BAn $BA0 speed conversion On
SPEED $BA1 speed conversion Off
CONVERSION
$MBn $MB set modem speed
$MB75 - CCITT V.23
$MB300 - 300 bps
$MB1200 - 1200 bps
$MB2400 - 2400 bps
$MB4800 - 4800 bps
$MB9600 - 9600 bps
$MB14400 - 14400 bps
$SBn $SB Set serial port speed
$SB300 - 300 bps
$SB1200 - 1200 bps
$SB2400 - 2400 bps
$SB4800 - 4800 bps
$SB9600 - 9600 bps
$SB19200 - 19200 bps
$SB38400 - 38400 bps
$SB56700 - 56700 bps
Leased/Dial-Up Commands
Function Command Description
LEASE LINE &L0 Enables dial-up mode.
(2/4-Wire,
&L2A Enables 2-wire operation in Answer
Answer/ mode.
Originate) &L2D Enables 2-wire operation in Originate
MODE SELECT mode.
&L4A Enables 4-wire operation in Answer mode.
&L4D Enables 4-wire operation in Originate mode.
Note: DIP-Switch #10 in UP position overrides &L commands.
Fax Commands
Function Command Description
ACTION +FDT Begin or continue sending
COMMANDS +FDT[=DF,VR,WD,LN] - Prefixes Phase C
data transmission. Subparameters (DF,VR,
WE,LN) are optional.
+FET End the Page or Document Command
+FET=<ppm> - Current or partial page is
complete; no more data appended to it.
PPM Codes are:
0 - Another page next, same document
1 - Another document next
2 - No more pages or documents
3 - Another partial page next
4 - Another page, procedure interrupt
5 - Another document, procedure
interrupt
6 - All done, procedure interrupt
+FK Kill operation, orderly fax abort
+FDR Begin or continue Phase C data
reception command
DCE +FDCS: Report DCS frame information
RESPONSES
+FDIS: Report DIS frame information
+FDTC: Report DTC frame information
FPOLL Indicates polling request
+FCFR Prepare to Receive Prompt
+FTSI: Report Remote ID Response, TSI
+FTSI:<string "__"> * - Transmit
Station ID
+FCSI: Report Remote ID Response, CIS
+FCSI:< string "__"> * - Called
Station ID
+FCIG: Report Remote ID Response, CIG
+FCIG:<string "__"> * - Polling
Station ID
+FNSF: Report received Non Standard
Facilities (NSF) Frame +FNSF:<string
"__"> * Non Standard Facilities
+FNSS: Report received Non Standard Setup
(NSS) Frame +FNSS:<string "__"> *Non
Standard Setup
+FNSC: Report received Non Standard Command
(NSC) Frame +FNSC:< string "__">
*Non Standard Commands
Notes
* String parameters consist of a double quote followed by the exact string value, including leading and trailing spaces, followed by the closing double quote.
** HDLC frame bytes consist of hexadecimal digits followed by a space
Function Command Description
DCE +FHT: Report Transmit HDLC Frame
RESPONSES Response
(Continued) +FHT<HDLC frame bytes> **- Reports
HDLC data sent by DCE
+FHR: Report Received HDLC Frame Response
+FHR<received HDLC frame bytes> ** -
Reports HDLC data received by DCE
+FCON Connection with a fax machine
+FVOICE Transition to Voice Response
+FET: Post Page Message Response
+FET:<ppm> PPM Codes are:
0 - Another page next, same document
1 - Another document next
2 - No more pages or documents
3 - Another partial page next
4 - Another page, procedure interrupt
5 - Another document, procedure
interrupt
6 - All done, procedure interrupt
+FPTS: Transmit Page Transfer Status Response
+FPTS:<ppr> - Reports number
representing copy quality and related
post-page messages from remote DCE.
PPR Codes are:
0 - Partial page errors
1 - Page good
2 - Page bad; retrain requested.
3 - Page good; retrain requested
4 - Page bad; interrupt requested
5 - Page good; interrupt requested
6 - Partial page reception failed after
4 retries (ECM only)
7 - Acknowledge a CTC message (ECM)
+FHNG: Call Termination Status Response
+FHNG:<hangup status code>
Hang-up Status Codes
0-9 - Call placement and termination
0 - Normal and proper end of connection
1 - Ring detect without successful
handshake
2 - Call aborted, from +FK or <CAN>
3 - No loop current
10-19 - Transmit Phase A &
miscellaneous errors
10 - Unspecified Phase A error
11 - No answer (T.30 T1 time-out)
Function Command Description
DCE +FHNG: 20-39 - Transmit Phase B hangup
RESPONSES codes
(Continued) 20 - Unspecified Transmit Phase B error
21 - Remote cannot receive or send
22 - COMREC error in transmit Phase B
23 - COMREC invalid command received
24 - RSPEC error
25 - DCS sent three times without
response
26 - DIS/DTC received 3 times; DCS not
recognized
27 - Failure to train at 2400 bps or
+FMINSP value
28 - RSPREC invalid response received
40-49 - Transmit Phase C Hangup
Codes
40 - Unspecified Transmit Phase C error
43 - DTE to DCE data underflow
50-69 - Transmit Phase D Hangup
Codes
50 - Unspecified Transmit Phase D error
51 - RSPREC error
52 - No response to MPS repeated 3 times
53 - Invalid response to MPS
54 - No response to EOP repeated 3 times
55 - Invalid response to EOP
56 - No response to EOM repeated 3 times
57 - Invalid response to EOM
58 - Unable to continue after PIN or PIP
70-89 - Receive Phase B Hangup
Codes
70 - Unspecified receive Phase B error
71 - RSPREC error
72 - COMREC error
73 - T.30 T2 timeout, expected page not
received
74 - T.30 T1 timeout after EOM received
90-99 - Received Phase C Hangup
Codes
90 - Unspecified receive phase C error
91 - Missing EOL after 5 seconds (section
3.2/T.4)
92 - Unused code
93 - DCE to DTE buffer overflow
94 - Bad CRC or frame (ECM or BFT modes)
Function Command Description
DCE +FHNG: 100- 119 - Receive Phase D Hangup
RESPONSES Codes
(Continued) 100 - Unspecified Received Phase D
errors
101 - RSPREC invalid response received
102 - COMREC invalid response received
103 - Unable to continue after PIN or
PIP
120-255 - Reserved Codes
PARAMETERS +FCLASS Service Class Identification and
Control
+FCLASS=<value> - Service Class set by
DTE:
+FCLASS=0 - Data modem
+FCLASS=1 - Service Class 1 (Not
Supported)
+FCLASS=2 - Service Class 2
+FCLASS=3-255 Reserved (Not Supported)
+FMFR DCE manufacture's name (Read only)
+FMDL DCE model's number (Read only)
+FREV DCE Revision number (Read only)
+FDCC DCE Capabilities Parameter
+FDCC=VR,BR,WD,LN,DF,EC,BF,ST
+FDIS Current Session Negotiation
Parameters
+FDIS=VR,BR,WD,LN,DF,EC,BF,ST
VR=0 - Normal, 98dpi
VR=1 - Fine, 196 dpi
BR=0 - 2400 bit/s V.27ter
BR=1 - 4800 bit/s V.27ter
BR=2 - 7200 bit/s V.29 or V.17
BR=3 - 9600 bit/s V.29 or V.17
WD=0 - 1728 pixels in 215 mm
WD=1 - 2048 pixels in 255 mm
WD=2 - 2432 pixels in 303 mm
WD=3 - 1216 pixels in 151 mm
WD=4 - 864 pixels in 107 mm
LN=0 - A4, 297 mm
LN=1 - B4, 364 mm
LN=2 - Unlimited Length
DF=0 - 1-D modified Huffman
DF=1 - 2-D modified Read (N/S)
DF=2 - 2-D Uncompressed Mode (N/S)
DF=3 - 2-D Modified Modified Read (N/S)
EC=0 - Disable ECM
EC=1 - Disable ECM, 64bytes/frame (N/S)
EC=2 - Disable ECM, 256bytes/frame (N/S)
BF=0 - Disable BFT (N/S)
BF=1 - Enable BFT (N/S)
Function Command Description
PARAMETERS +FDCS VR=Normal VR=Fine
(Continued) (Cont'd) ST=0 0 ms 0 ms
ST=1 5 ms 5 ms
ST=2 10 ms 5 ms
ST=3 10 ms 10 ms
ST=4 20 ms 10 ms
ST=5 20 ms 20 ms
ST=6 40 ms 20 ms
ST=7 40 ms 40 ms
+FLID Local ID String Parameter,TSI/CSI
+FLID=<local ID string> - Local ID
string is 20 ASCII characters (0-9,+
and space).
+FCIG Local Polling ID String Parameter
+FCIG=<local polling ID string> - Local
polling ID string is 20 ASCII characters.
+FSPL Enable Polling Parameter
+FSPL=0 - DTE does not want to poll.
+FSPL=1 - DTE can receive a polled
document.
+FLPL Document for Polling Parameter
+FLPL=0 - DTE has no document to poll.
+FLPL=1 - DTE has a document ready for
polling.
+FPTS Page Transfer Status Parameter
+FPTS=0 - Partial page errors.
+FPTS=1 - Page good.
+FPTS=2 - Page bad; retrain requested.
+FPTS=3 - Page good; retrain requested.
+FPTS=4 - Page bad; interrupt requested.
+FPTS=5 - Page good; interrupt requested.
+FBUG Session Message Reporting Parameter
+FBUG=0 - Disables HDLC frame reporting.
+FBUG=1 - DCE reports contents of Phase
B and D HDLC frames as sent and received
and other responses.
OPTION +FCR Capability to Receive Parameter
PARAMETERS +FCR=0 - DCE will not receive message
data.
+FCR=1 - DCE can receive message data.
+FAA Auto Answer Mode Parameter
+FAA=0 - Constrains DCE to answer as set
by +FCLASS.
+FAA=1 - DCE can answer and automatically
determine whether to answer as a
facsimile DCE or as a data modem.
Function Command Description
OPTION +FBUF Buffer Size (Read Only) Parameter
PARAMETERS +FBUF?<bs>,<xoft>,<xont>,<bc>
(Continued) BS - Total buffer size
XOFT - XOFF threshold
XONT - XON threshold
BC - Current buffer byte count
+FCQ Copy Quality Capabilities Parameter
+FCQ=0 - DCE does no copy quality checking.
+FCQ=1 - DCE can check 1-D Phase C data.
+FBADMUL Error Threshold Multiplier -
+FBADMUL=<value> - Value is 0 to 255.
Number of lines received with bad pixel
count is multiplied by this number. If
value exceeds number of lines in page,
then error rate is too high.
+FBADLIN Number of Consective Bad Lines for a Bad
Page Parameter -
+FBADLIN=<value> - Value is 0 to 155.
If consecutive lines have pixel count
errors in normal resolution mode, the
copy quality is unacceptable. If two
consecutive lines have pixel count errors in fine resolution mode, the copy quality is unacceptable.