|
US ROBOTICS 28,800 EXTERNAL
3COM CORPORATION
US ROBOTICS 28,800 EXTERNAL
|
Modem Type
|
Data (synchronous/asynchronous)/Fax
|
|
Maximum Data Rate
|
28.8Kbps
|
|
Maximum Fax Rate
|
14.4Kbps
|
|
Data Bus
|
External
|
|
Fax Class
|
Class I & II
|
|
Data Modulation Protocol
|
Bell 103A/212A
ITU-T V.22, V.22bis, V.23, V.32, V.32bis, V.25
|
|
Fax Modulation Protocol
|
ITU-T V.17, V.21CH2, V.27ter, V.29
|
|
Error Correction/Compression
|
MNP5, V.42, V.42bis
|

|
CONNECTIONS
|
|
Purpose
|
Location
|
Purpose
|
Location
|
|
Line out
|
CN3
|
DC power
|
CN1
|
|
Line in
|
CN4
|
Volume
|
R1
|
|
RS-232/422
|
CN2
|
Power switch
|
SW2
|
|
DTR SIGNAL
|
|
Setting
|
SW1/1
|
|
í DTR normal
|
Off
|
|
DTR forced high
|
On
|
|
RESULT CODES
|
|
Setting
|
SW1/2
|
|
í Verbal result codes enabled
|
Off
|
|
Numeric result codes enabled
|
On
|
|
RESULT CODES DISPLAY
|
|
Setting
|
SW1/3
|
|
í Enabled
|
On
|
|
Disabled
|
Off
|
|
ECHO DISPLAY
|
|
Setting
|
SW1/4
|
|
í Enabled
|
Off
|
|
Disabled
|
On
|
|
AUTO ANSWER
|
|
Setting
|
SW1/5
|
|
í Disabled
|
On
|
|
Enabled
|
Off
|
|
CARRIER DETECT
|
|
Setting
|
SW1/6
|
|
í CD normal
|
Off
|
|
CD forced high
|
On
|
|
SOFTWARE RESET
|
|
Setting
|
SW1/7
|
|
í CD normal
|
Off
|
|
CD forced high
|
On
|
|
AT COMMAND SET
|
|
Setting
|
SW1/8
|
|
Enabled
|
On
|
|
Disabled
|
Off
|
|
DIAGNOSTIC LED(S)
|
|
LED
|
Color
|
Status
|
Mode
|
Condition
|
|
AA
|
Red
|
On
|
Answer
|
Auto-answer enabled
|
|
AA
|
Red
|
Off
|
N/A
|
Auto-answer disabled
|
|
AA
|
Red
|
Blinking
|
N/A
|
Phone is ringing
|
|
CD
|
Red
|
On
|
N/A
|
Carrier signal detected
|
|
CD
|
Red
|
Off
|
N/A
|
Carrier signal not detected
|
|
RD
|
Red
|
Blinking
|
N/A
|
Modem is receiving data or sending result codes
|
|
RD
|
Red
|
Off
|
N/A
|
Modem is not receiving data
|
|
SD
|
Red
|
Blinking
|
N/A
|
Modem is transmitting data
|
|
SD
|
Red
|
Off
|
N/A
|
Modem is not transmitting data
|
|
TR
|
Red
|
On
|
N/A
|
DTR signal is high
|
|
TR
|
Red
|
Off
|
N/A
|
DTR signal is low
|
|
CS
|
Red
|
On
|
N/A
|
CTS high
|
|
CS
|
Red
|
Off
|
N/A
|
CTS normal
|
|
ARQ/FAX
|
Red
|
On
|
Data
|
Error control connection established
|
|
ARQ/FAX
|
Red
|
Blinking
|
Data
|
Error control data is being transmitted
|
|
ARQ/FAX
|
Red
|
Blinking
|
Fax
|
Modem is connected in FAX mode
|
Proprietary AT Command Set
|
BIT-MAPPED REGISTER S13
|
|
Format:
|
AT [cmds] S13=n [cmds]
|
|
Example:
|
ATS13=13 <CR>
|
|
Default:
|
0
|
|
Range:
|
0 - 89
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Controls DTR reset, DTR dialing, reset dialing, and MNP3.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
1
|
DTR normal.
Reset on low DTR.
|
|
1
|
í 0
|
Not used.
|
|
2
|
í 0
|
Not used.
|
|
3
|
í 0
1
|
DTR dialing disabled.
DTR dialing enabled.
|
|
4
|
í 0
1
|
Reset dialing disabled.
Reset dialing enabled.
|
|
5
|
í 0
|
Not used.
|
|
6
|
í 0
1
|
MNP 3 enabled.
MNP 3 disabled.
|
|
7
|
í 0
|
Not used.
|
|
BIT-MAPPED REGISTER S15
|
|
Format:
|
AT [cmds] S15=n [cmds]
|
|
Example:
|
ATS15=13 <CR>
|
|
Default:
|
0
|
|
Range:
|
0 - 56
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Controls non-error-correcting mode buffer, MNP4, and BS/DEL switch.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
|
Not used.
|
|
1
|
í 0
|
Not used.
|
|
2
|
í 0
|
Not used.
|
|
3
|
í 0
1
|
Non-error-correcting mode transmit buffer set to 1.5KB.
Non-error-correcting mode transmit buffer set to 128 bytes.
|
|
4
|
í 0
1
|
MNP 4 enabled.
MNP 4 disabled.
|
|
5
|
í 0
1
|
Use backspace key for delete disabled.
Use backspace key for delete enabled.
|
|
BIT-MAPPED REGISTER S27
|
|
Format:
|
AT [cmds] S27=n [cmds]
|
|
Example:
|
ATS27=139 <CR>
|
|
Default:
|
0
|
|
Range:
|
0 - 191
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Controls V.21, V.32 encoding and modulation, V.42 answer tone and handshake, and 9600 result codes.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
1
|
V.21 disabled.
V.21 enabled.
|
|
1
|
í 0
1
|
V.32 trellis coding disabled.
V.32 trellis coding enabled.
|
|
2
|
í 0
1
|
V.32 modulation enabled.
V.32 modulation disabled.
|
|
3
|
í 0
1
|
2100Hz answer tone enabled.
2100Hz answer tone disabled.
|
|
5, 4
|
í 00
01
10
11
|
V.42 detect, LAPM and MNP enabled.
V.42 detect and LAPM enabled.
MNP enabled.
LAPM enabled.
|
|
6
|
í 0
|
Not used.
|
|
7
|
í 0
1
|
Actual result codes displayed.
Force 9600 result codes.
|
|
COMPRESSION AND ERROR CORRECTION
|
|
Format:
|
AT [cmds] S51=n [cmds]
|
|
Example:
|
ATS51=3 <CR>
|
|
Default:
|
0
|
|
Range:
|
0 - 7
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Selects compression and error correction for specific modulations.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
1
|
MNP/V.42 enabled during V.22 operation.
MNP/V.42 disabled during V.22 operation.
|
|
1
|
í 0
1
|
MNP/V.42 enabled during V.22bis operation.
MNP/V.42 disabled during V.22bis operation.
|
|
2
|
í 0
1
|
MNP/V.42 enabled during V.32bis operation.
MNP/V.42 disabled during V.32bis operation.
|
|
BIT-MAPPED REGISTER S56
|
|
Format:
|
AT [cmds] S56=n [cmds]
|
|
Example:
|
ATS56=139 <CR>
|
|
Default:
|
0
|
|
Range:
|
0 - 223
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Controls non-linearing coding, TX level deviation, pre-emphasis, pre-coding, shaping, V.34, and V.FC.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
1
|
Non linearing coding enabled.
Non linearing coding disabled.
|
|
1
|
í 0
1
|
TX level deviation enabled.
TX level deviation disabled.
|
|
2
|
í 0
1
|
Pre-emphasis enabled.
Pre-emphasis disabled.
|
|
3
|
í 0
1
|
Pre-coding enabled.
Pre-coding disabled.
|
|
4
|
í 0
1
|
Shaping enabled.
Shaping disabled.
|
|
5
|
í 0
|
Not used.
|
|
6
|
í 0
1
|
V.34 enabled.
V.34 disabled.
|
|
7
|
í 0
1
|
V.FC enabled.
V.FC disabled.
|
|
BREAK LENGTH
|
|
Type:
|
Register
|
|
Format:
|
AT [cmds] S21=n [cmds]
|
|
Example:
|
ATS21=20 <CR>
|
|
Default:
|
10
|
|
Range:
|
0-255
|
|
Unit:
|
10 ms
|
|
Description:
|
Sets the length of error correction mode breaks sent from DCE to DTE in ARQ mode.
|
|
BREAK TYPE
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &Yn [cmds]
|
|
Example:
|
AT &Y0 <CR>
|
|
Description:
|
Configures action of break signal.
|
|
Command
|
Function
|
|
&Y0
|
Break empties buffer.
|
|
í &Y1
|
Break empties buffer and is sent immediately.
|
|
&Y2
|
Break does not empty buffer and is sent immediately.
|
|
CONNECTION SPEED UPPER LIMIT
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &Nn [cmds]
|
|
Example:
|
AT &N1 DT555-1212 <CR>
|
|
Description:
|
Sets required connection speed if &U is set to 0. Otherwise, sets fastest allowed connection speed.
|
|
Command
|
Function
|
|
í &N0
|
Variable.
|
|
&N1
|
300bps
|
|
&N2
|
1200bps
|
|
&N3
|
2400bps
|
|
&N4
|
4800bps
|
|
&N5
|
7200bps
|
|
&N6
|
9600bps
|
|
&N7
|
12Kbps
|
|
&N8
|
14.4Kbps
|
|
&N9
|
16.8Kbps
|
|
&N10
|
19.2Kbps
|
|
&N11
|
21.6Kbps
|
|
&N12
|
24Kbps
|
|
&N13
|
26.4Kbps
|
|
&N14
|
28.8Kbps
|
|
CONNECTION SPEED LOWER LIMIT
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &Un [cmds]
|
|
Example:
|
AT &U1 DT555-1212 <CR>
|
|
Description:
|
Sets slowest allowed connection speed if &N is set to 1 or higher.
|
|
Command
|
Function
|
|
í &U0
|
Disabled.
|
|
&U1
|
300bps
|
|
&U2
|
1200bps
|
|
&U3
|
2400bps
|
|
&U4
|
4800bps
|
|
&U5
|
7200bps
|
|
&U6
|
9600bps
|
|
&U7
|
12000bps
|
|
&U8
|
14400bps
|
|
&U9
|
16800bps
|
|
&U10
|
19200bps
|
|
&U11
|
21600bps
|
|
&U12
|
24000bps
|
|
&U13
|
26400bps
|
|
&U14
|
28800bps
|
|
ERROR CONTROL MODE
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &Mn [cmds]
|
|
Example:
|
AT &M1 %C1 <CR>
|
|
Description:
|
Selects active error-control protocols.
|
|
Command
|
Function
|
|
&M0
|
Normal mode, error control disabled.
|
|
í &M4
|
Normal/ARQ.
|
|
&M5
|
ARQ mode.
|
|
ESCAPE CHARACTER RESPONSE
|
|
Type:
|
Register
|
|
Format:
|
AT [cmds] S14=n [cmds]
|
|
Example:
|
ATS14=0 <CR>
|
|
Default:
|
0
|
|
Description:
|
Controls reaction to escape character.
|
|
Command
|
Function
|
|
í S14=0
|
Normal operation.
|
|
S14=1
|
When +++ is received, modem goes on hook, enters command state and sends NO CARRIER result code.
|
|
EXTENDED RESULT CODES
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &An [cmds]
|
|
Example:
|
AT &A1 %C1 <CR>
|
|
Description:
|
Selects extended result codes.
|
|
Command
|
Function
|
|
&A0
|
Extended result codes disabled.
|
|
&A1
|
ARQ result codes enabled.
|
|
&A2
|
V.32 result code enabled.
|
|
í &A3
|
Error correction and compression result codes enabled.
|
|
FLOW CONTROL CHARACTER - XON
|
|
Type:
|
Register
|
|
Format:
|
AT [cmds] S22=n [cmds]
|
|
Example:
|
ATS22=20 <CR>
|
|
Default:
|
17
|
|
Range:
|
0-127
|
|
Unit:
|
ASCII
|
|
Description:
|
Sets the character used to represent XON.
|
|
FLOW CONTROL CHARACTER - XOFF
|
|
Type:
|
Register
|
|
Format:
|
AT [cmds] S23=n [cmds]
|
|
Example:
|
ATS23=20 <CR>
|
|
Default:
|
19
|
|
Range:
|
0-127
|
|
Unit:
|
ASCII
|
|
Description:
|
Sets the character used to represent XOFF.
|
|
FLOW CONTROL PASSTHROUGH
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &In [cmds]
|
|
Example:
|
AT &I0 &W <CR>
|
|
Description:
|
Allows modem to act on, then transmit XON/XOFF characters.
|
|
Command
|
Function
|
|
í &I0
|
Software flow control disabled.
|
|
&I1
|
XON/XOFF passthrough enabled.
|
|
&I2
|
XON/XOFF passthrough disabled.
|
|
FLOW CONTROL TYPE
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &Hn [cmds]
|
|
Example:
|
AT &H0 A <CR>
|
|
Description:
|
Sets type of flow control used by modem.
|
|
Command
|
Function
|
|
&H0
|
Flow control disabled.
|
|
í &H1
|
CTS/RTS flow control enabled.
|
|
&H2
|
XON/XOFF flow control enabled.
|
|
&H3
|
CTS/RTS and XON/XOFF flow control enabled.
|
|
HELP SCREENS
|
|
Type:
|
Immediate
|
|
Format:
|
AT <prefix>$
|
|
Example:
|
AT &$ <CR>
|
|
Description:
|
Shows command help screens for all commands beginning with the given prefix, or no prefix if none is given.
|
|
Command
|
Function
|
|
$
|
Shows AT help screen.
|
|
&$
|
Shows AT& help screen.
|
|
INACTIVITY TIMER
|
|
Type:
|
Register
|
|
Format:
|
AT [cmds] S19=n [cmds]
|
|
Example:
|
ATS19=20 <CR>
|
|
Default:
|
0
|
|
Range:
|
Unidentified
|
|
Unit:
|
1 minute
|
|
Description:
|
Sets the length of time that the modem does not receive information before it disconnects.
|
|
LOCK SERIAL PORT
|
|
Type:
|
Configuration
|
|
Format:
|
AT [cmds] &Bn [cmds]
|
|
Example:
|
AT &N9 &B0 <CR>
|
|
Description:
|
Sets operation of serial port speed.
|
|
Command
|
Function
|
|
&B0
|
Serial speed follows connect speed.
|
|
í &B1
|
Serial speed locked.
|
|
&B2
|
Serial speed locked in ARQ mode only.
|
|
MAPPING
|
|
Format:
|
AT [cmds] S55=n [cmds]
|
|
Example:
|
ATS55=13 <CR>
|
|
Default:
|
0
|
|
Range:
|
0 - 15
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Controls mapping.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
1
|
8S-2D map enabled.
8S-2D map disabled.
|
|
1
|
í 0
1
|
16S-4D map enabled.
16S-4D map disabled.
|
|
2
|
í 0
1
|
32S-2D map enabled.
32S-2D map disabled.
|
|
3
|
í 0
1
|
64S-4D map enabled.
64S-4D map disabled.
|
|
REPORT INFORMATION
|
|
Type:
|
Immediate
|
|
Format:
|
AT [cmds] In [cmds]
|
|
Example:
|
AT I1 O <CR>
|
|
Description:
|
Displays modem properties.
|
|
Command
|
Function
|
|
I0
|
Reports product code.
|
|
I1
|
Reports ROM checksum result.
|
|
I2
|
Reports RAM checksum result.
|
|
I3
|
Reports firmware version.
|
|
I4
|
Reports current command settings.
|
|
I5
|
Reports current NVRAM settings.
|
|
I6
|
Reports current connection’s statistics.
|
|
I7
|
Reports configuration.
|
|
BAUD RATE
|
|
Format:
|
AT [cmds] S54=n [cmds]
|
|
Example:
|
ATS54=139 <CR>
|
|
Default:
|
0
|
|
Range:
|
0 - 255
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Controls baud rate.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
1
|
2400 baud rate enabled.
2400 baud rate disabled.
|
|
1
|
í 0
1
|
2743 baud rate enabled.
2743 baud rate disabled.
|
|
2
|
í 0
1
|
2800 baud rate enabled.
2800 baud rate disabled.
|
|
3
|
í 0
1
|
3000 baud rate enabled.
3000 baud rate disabled.
|
|
4
|
í 0
1
|
3200 baud rate enabled.
3200 baud rate disabled.
|
|
5
|
í 0
1
|
3429 baud rate enabled.
3429 baud rate disabled.
|
|
6
|
í 0
1
|
Call indicate during V.34 operation enabled.
Call indicate during V.34 operation disabled.
|
|
7
|
í 0
1
|
V.8 during V.34 operation enabled.
V.8 during V.34 operation disabled.
|
|
TONE DIALING TEST
|
|
Type:
|
Register
|
|
Format:
|
AT [cmds] S16=n [cmds]
|
|
Example:
|
ATS16=1 <CR>
|
|
Description:
|
Selects the tone dialing test
|
|
Command
|
Function
|
|
í S16=0
|
Tone dialing test disabled.
|
|
S16=1
|
Tone dialing test enabled.
|
|
V.32 AND V.32bis MODULATIONS
|
|
Format:
|
AT [cmds] S34=n [cmds]
|
|
Example:
|
ATS34=13 <CR>
|
|
Default:
|
6
|
|
Range:
|
0 - 15
|
|
Unit:
|
Bit-mapped
|
|
Description:
|
Controls V.32 and V.32bis modulations.
|
|
Bit
|
Value
|
Function
|
|
0
|
í 0
1
|
V.32bis enabled.
V.32bis disabled.
|
|
1
|
í 1
|
Not used.
|
|
2
|
í 1
|
Not used.
|
|
3
|
í 0
1
|
V.32 modulation disabled.
V.32 modulation enabled.
|
|
V.32 HANDSHAKE TIME
|
|
Type:
|
Register
|
|
Format:
|
AT [cmds] S28=n [cmds]
|
|
Example:
|
ATS28=20 <CR>
|
|
Default:
|
8
|
|
Range:
|
0-255
|
|
Unit:
|
.1 second
|
|
Description:
|
Sets length of V.32 handshake.
|
|