3COM CORPORATION

COURIER HST WITH ASL

Modem Type

Data (synchronous/asynchronous)

Maximum Data Rate

14.4Kbps

Data Bus

External

Data Modulation Protocol

Bell 103A/212A

ITU-T V.22, V.22bis, V.23

Error Correction/Compression

MNP5, V.42, V.42bis

CONNECTIONS

Purpose

Location

Purpose

Location

Line out

CN1

DC power

CN4

Line in

CN2

Volume

R1

RS-232/422

CN3

Power switch

SW2

MI/MIC POLARITY

Setting

J6

J8

» Normal

Pins 1 & 2 closed

Pins 1 & 2 closed

Reversed

Pins 2 & 3 closed

Pins 2 & 3 closed

TX/RX PIN ASSIGNMENT

Setting

SW3

Normal operation

» Off

Reverse TX/RX pin assignments

On

DTR SIGNAL

Setting

SW1/1

DTR forced high

On

» DTR normal

Off

RESULT CODES

Setting

SW1/2

» Verbose result codes enabled

Off

Numeric result codes enabled

On

RESULT CODES DISPLAY

Setting

SW1/3

» Display enabled

On

Display disabled

Off

ECHO COMMANDS DISPLAY

Setting

SW1/4

» Local echo enabled

Off

Local echo disabled

On

AUTO ANSWER

Setting

SW1/5

» Modem answers on first ring

On

Modem does not answer on first ring

Off

CARRIER DETECT

Setting

SW1/6

» CD normal

Off

CD forced high

On

RESULT CODES DISPLAY

Setting

SW1/7

» Display result codes in originate and answer modes

Off

Display result codes in Answer mode

On

AT COMMAND SET

Setting

SW1/8

» AT command set enabled

On

AT command set disabled

Off

ESCAPE CODE

Setting

SW1/9

» Off

Disconnect, go to command mode and display NO CARRIER when escape character is received

On

Go to command mode and display OK result code when escape character is received

USER PROFILE

Setting

SW1/10

» Off

Use stored profile

On

Use factory default

VOICE/DATA

Setting

SW4

Note: for switch functions see table for register S32.

DIAGNOSTIC LED(S)

LED

Color

Status

Condition

HS

Red

On

Modem is operating at 4800bps or faster

HS

Red

Off

Modem is operating at slower than 4800bps

AA

Red

On

Auto-answer enabled

AA

Red

Off

Auto-answer disabled

CD

Red

On

Carrier signal detected

CD

Red

Off

Carrier signal not detected

OH

Red

On

Modem is off-hook

OH

Red

Off

Modem is on-hook

RD

Red

Blinking

Modem is receiving data

RD

Red

Off

Modem is not receiving data

TD

Red

Blinking

Modem is transmitting data

TD

Red

Off

Modem is not transmitting data

TR

Red

On

DTR signal is high

TR

Red

Off

DTR signal is low

MR

Red

On

Power is on

MR

Red

Off

Power is off

MR

Red

Blinking

Retraining/test mode

RS

Red

On

RTS signal is high

RS

Red

Off

RTS signal is low

CS

Red

On

CTS signal is high

CS

Red

Off

CTS signal is low

EC

Red

On

Error control enabled

EC

Red

Off

Error control disabled

EC

Red

Blinking

Modem is retransmitting data

SYN

Red

On

Synchronous mode

SYN

Red

Off

Asynchronous mode

Proprietary AT Command Set

BIT-MAPPED REGISTER S13

Format

AT [cmds] S13=n [cmds]

Example:

ATS13=139<CR>

Default:

0

Range:

0 - 255

Unit:

Bit-mapped

Description:

Controls DTR reset, DTR dialing, auto answer, result code delay, reset dialing, HST and MNP3.

Bit

Value

Function

0

» 0

1

DTR normal.

Reset on low DTR.

1

» 0

1

Auto answer operation normal.

When ring detected, enter originate mode and listen for answer tone.

2

» 0

1

Pause 250 msec. before displaying result codes.

Display result codes immediately.

3

» 0

1

DTR dialing disabled.

DTR dialing enabled.

4

» 0

1

Reset dialing disabled.

Reset dialing enabled.

5

» 0

1

HST enabled.

HST disabled.

6

» 0

1

MNP 3 enabled.

MNP 3 disabled.

BIT-MAPPED REGISTER S15

Format:

AT [cmds] S15=n [cmds]

Example:

ATS15=139<CR>

Default:

0

Range:

0 - 127

Unit:

Bit-mapped

Description:

Controls HST high frequency equalization, online fallback, back channel, non-error-correcting mode buffer, MNP4, and BS/DEL switch and MNP compliance

Bit

Value

Function

0

» 0

1

HST high frequency equalization enabled.

HST high frequency equalization disabled.

1

» 0

1

Online fallback enabled.

Online fallback disabled.

2

» 0

1

450bps back channel enabled.

450bps back channel disabled.

3

» 0

1

Non-error-correcting mode transmit buffer set to 1.5KB.

Non-error-correcting mode transmit buffer set to 128 bytes.

4

» 0

1

MNP 4 enabled.

MNP 4 disabled.

5

» 0

1

Use backspace key for delete disabled.

Use backspace key for delete enabled.

6

» 0

1

MNP normal.

MNP adjusted for non compliant modems.

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.42 answer tone and handshake, and 9600 result codes.

Bit

Value

Function

0

» 0

1

V.21 disabled.

V.21 enabled.

1

» 0

Not used.

2

» 0

Not used.

3

» 0

1

2100Hz answer tone enabled.

2100Hz answer tone disabled.

5, 4

» 00

01

10

11

V.42 detect, LAPM and MNP enabled.

V.42 detect and LAPM enabled.

MNP enabled.

LAPM enabled.

6

» 0

Not used.

7

» 0

1

Actual result codes displayed.

Force 9600 result codes.

BREAK LENGTH

Type:

Register

Format:

AT [cmds] S21=n [cmds]

Example:

ATS21=20<CR>

Default:

10

Range:

Unidentified

Unit:

10 ms

Description:

Sets the length of error control mode breaks sent from DCE to DTE.

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.

» &Y1

Break empties buffer and is sent immediately.

&Y2

Break does not empty buffer and is sent immediately.

COMPRESSION

Type:

Configuration

Format:

AT [cmds] &Kn [cmds]

Example:

AT &K1<CR>

Description:

Controls data compression.

Command

Function

&K0

Data compression disabled.

&K1

Data compression disabled when serial port is locked.

&K2

Data compression enabled.

&K3

MNP 5 disabled.

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

» &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

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.

» &A3

Error control and compression result codes enabled.

FLOW CONTROL CHARACTER - XON

Type:

Register

Format:

AT [cmds] S22=n [cmds]

Example:

ATS22=20<CR>

Default:

17

Range:

11-127

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:

11-127

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

» &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.

» &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 ATx help screen.

&$

Shows AT&x help screen.

D$

Shows ATDx help screen.

S$

Shows S-register 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.

NETWORK ACCESS

Type:

Configuration

Format:

AT [cmds] %Rn [cmds]

Example:

AT %R1 &W<CR>

Description:

Used with USR network management system.

Command

Function

» %R0

Network access disabled.

%R1

Network access enabled.

REPEAT COMMAND STRING

Type:

Configuration

Format:

AT [cmds] > [cmds]

Example:

AT *D1 > #E1<CR>

Description:

Causes modem to repeat command string until a keyboard key is pressed.

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.

STATUS REGISTER BIT

Type:

Configuration

Format:

Read: AT [cmds] Sn.m=0 or 1 [cmds]

Write: AT [cmds] Sn.m=? [cmds]

Example:

AT S40.4=1 S51.3?<CR>

Description:

Sets/clears or reads bit m of register n.

TESTING

Format

AT [cmds] S16=n [cmds]

Example:

ATS16=32<CR>

Default:

0

Range:

0 - 15

Unit:

Bit-mapped

Description:

Enables loopback tests.

Note:

Bit 3 is read-only.

Bit

Value

Function

0

» 0

1

Analog loopback test disabled.

Analog loopback test enabled.

1

» 0

1

Dial test disabled.

Dial test enabled.

2

» 0

1

Test pattern disabled.

Test pattern enabled.

3

» 0

1

Remote digital loopback test disabled.

Remote digital loopback test enabled.

TIME DISPLAY

Type:

Immediate

Format:

AT [cmds] Kn [cmds]

Example:

AT K1 *L2 #E1<CR>

Description:

Displays the current call time or clock time.

Command

Function

K0

Display length of last call.

K1

Display actual time.

TOUCH TONE RECOGNITION

Type:

Configuration

Format:

AT [cmds] %Tn [cmds]

Example:

AT %T &W<CR>

Description:

Controls recognition of touch tones while off hook.

Command

Function

%T

Enabled.

BIT MAPPED REGISTER S34

Format:

AT [cmds] S34=n [cmds]

Example:

ATS34=139<CR>

Default:

0

Range:

0 - 56

Unit:

Bit-mapped

Description:

Controls V.23, MR LED function and MI/MIC.

Bit

Value

Function

3

» 0

1

V.23 disabled.

V.23 enabled.

4

» 0

1

MR LED normal.

MR LED reflects DSR signal.

5

» 0

1

MI/MIC disabled.

MI/MIC enabled.

VOICE/DATA SWITCH

Type:

Register

Format:

AT [cmds] S32=n [cmds]

Example:

ATS32=6<CR>

Default:

1

Unit:

1-7

Description:

Controls the function of SW4.

Command

Function

0

Disabled.

1

Switch between voice and originate mode.

2

Switch between voice and answer mode.

3

Redial.

4

Dial number stored at position 0.

5

Enable and disable Auto Answer.

6

Reset.

7

Start remote digital loopback test.