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MICRO LINK 1200

3COM CORPORATION

MICRO LINK 1200

Card Type

Modem (asynchronous)

Chip Set

U.S. Robotics

Maximum Data Rate

1200bps/300bps

Data Bus

External

Data Modulation Protocol

Bell 212A

54162

CONNECTIONS

Function

Label

Function

Label

Line out/in - unidentified

CN1

DC power

CN4

Line in/out - unidentified

CN2

Power switch

SW1

RS-232/422

CN3

Analog loopback switch

SW2

USER CONFIGURABLE SETTINGS

Setting

Label

Position

Auto answer

SW3/A

Off

Continuous answer

SW3/A

On

CD normal

SW3/B

Off

CD forced high

SW3/B

On

Equalize for dial-up phone lines

SW3/C

Off

Equalize for dedicated phone lines

SW3/C

On

DTR normal

SW3/D

Off

DTR forced high

SW3/D

On

í A/A1 normal

J/1

Unidentified

A/A1 low when modem is off-hook

J/1

Unidentified

í 10-bit character transmission

J/2

Unidentified

11-bit character transmission

J/2

Unidentified

í Future application - factory configured, do not alter

J/3

Unidentified

í Reset

J/14

Unidentified

RS232C

Setting

SW4/A

SW4/B

SW4/C

SW4/D

Pin 2 receive/Pin 3 send

On

On

Off

Off

Pin 2 send/Pin 3 receive

Off

Off

On

On

SERIAL PORT ADDRESS

Setting

Setting

J/10

J/11

J/12

COM1 (3F8h)

IRQ4

On

On

On

COM2 (2F8h)

IRQ3

On

Off

Off

COM3 (3E8h)

IRQ4

Off

On

On

COM4 (2E8h)

IRQ3

Off

Off

Off

DIAGNOSTIC LED(S)

LED

Color

Status

Condition

CD

Red

On

Carrier signal detected

CD

Red

Off

Carrier signal not detected

ON

Red

On

Power is on

ON

Red

Off

Power is off

AL

Red

On

Modem is in analog loopback test mode

AL

Red

Off

Modem is not in analog loopback test mode

SD

Red

On

Modem is transmitting data

SD

Red

Off

Modem is not transmitting data

RD

Red

On

Modem is receiving data

RD

Red

Off

Modem is not receiving data

MISCELLANEOUS TECHNICAL NOTES

Note: Diagram not available.

Proprietary AT Command Set

ABORT

Type:

Immediate

Format:

Any key

Description:

Aborts dialing command issued; modem hangs up.

ANSWER

Type:

Immediate

Format:

AT [cmds] A

Description:

Enables answer mode, the modem goes off-hook.

ATTENTION

Type:

Immediate

Format:

AT [cmds]

Description:

Tells the modem that a command follows or use alone to test OK result code

DIAL

Type:

Immediate

Format:

AT [cmds] D<#> [cmds]

Example:

ATDT 443-3388,,,1111;

Description:

Dials telephone number according to any modifiers included in the string

Note:

Any combination of modifiers can be used to produce the desired dial functions in sequence.

Command

Function

í P

Pulse dialing enabled

T

Tone dialing enabled

,

Dialing paused for 2 seconds to a maximum amount of time specified in S8 register

ECHO

Type:

Configuration

Format:

AT [cmds] En [cmds]

Description:

Controls echo function; display keyboard commands when enabled.

Command

Function

í E0

Echo function disabled

E1

Echo function enabled

ECHO - ON-LINE

Type:

Configuration

Format:

AT [cmds] Fn [cmds]

Description:

Selects whether commands sent while in data mode are echoed

Command

Function

F0

Local echo enabled

í F1

Local echo disabled

ESCAPE SEQUENCE

Type:

Immediate

Format:

+++AT [cmds] <CR>

Description:

Initiates the escape sequence and returns the modem to the on-line command state if it receives three escape characters set in S2 within the time allotted by S12.

Note: Do not precede this command with AT.

REPEAT PREVIOUS COMMAND

Type:

Immediate

Format:

A/

Description:

Repeats previous command, mainly used for redial

Note: Do not precede this command with AT, or follow it with <CR>.

RESULT CODES

Type:

Configuration

Format:

AT [cmds] Qn [cmds]

Description:

Enables modem to send result codes to the DTE

Command

Function

í Q0

Result code sending enabled

Q1

Result code sending disabled

RESULT CODE FORMAT

Type:

Configuration

Format:

AT [cmds] Vn [cmds]

Description:

Selects word or numeric format for information-text and result codes

Command

Function

V0

Numeric format enabled

í V1

Verbose (word) format enabled

SPEAKER MODE

Type:

Configuration

Format:

AT [cmds] Mn [cmds]

Description:

Selects various speaker options

Command

Function

M0

Speaker disabled

í M1

Speaker enabled until carrier signal detected

M2

Speaker enabled

STATUS-REGISTER

Type:

Configuration

Format:

AT [cmds] Sn=x [cmds]

Description:

Writes to a specified register, values ranging from 0-255.

Command

Function

S0=x

Sets the number of rings allowed before the modem automatically goes off-hook.

Default = 1

S2=x

Selects a character used for the escape sequence.

Default = 43

S7=x

Maximum wait time in seconds the modem uses after dialing to detect a carrier signal from the remote modem for both originating and answering calls.

Default = 17