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AT and AT& (Ampersand):   Motorola SM56 Software Modem User's Guide

The modem responds to the following AT and AT& command options.

The letters AT (or at) must precede all commands except A/ and +++. Factory-default options are underlined.

Command Option Description

A

(none)

Answer incoming call

A/

(none)

 

Repeat Last Command

Re-issues the previous command to the modem.

(Do not press Return; the command executes as soon as the / is pressed.)

D

(none)

 

Dial a Number

Instructs the modem to dial the telephone number that you enter immediately after the ATD command. Example: ATD5554678.

NOTE: If multiple ATD commands are used in speakerphone mode, the modem must be forced to blind-dial after dial-tone detection.

E

 

Echo Async (Keyboard) Input to Terminal

Determines whether the characters you type at the keyboard are displayed (echoed) to the terminal-emulation window (if it is active) or to the communications application.

 

E0

Disable

 

E1

Enable

H

 

Hook

 

H0

Go on Hook (disconnect from the telephone line; hang up)

 

H1

Go off Hook (connect to the telephone line)

I

 

Request Information From Modem

 

I0

“5600”

 

I1

“255”

 

I2

“OK”

 

I3

Software Version

 

I4

“OK”

 

I5

Disconnect Reason

 

I6

Country Code

 

I7

Product Code

L

 

Speaker Volume

This parameter determines the volume, for call-progress monitor only, of sounds such as dialing, ringing, busy, negotiation.

 

L0, L1

Low

 

L2

Medium

 

L3

High

M

 

Speaker Control

 

M0

Off

 

M1

On During Training Only

 

M2

Always On

 

M3

Off during dialing; on during call progress; off during data transfer

O

 

Return to On-Line Mode

This parameter determines whether the modem initiates a retrain after changing from escape mode to data mode, or after a semi-colon in dial strings.

 

O0

No Retrain

 

O1

Retrain

 

O2

Initiate Rate Renegotiation

 

O3

Rate Renegotiation with silence

P

P

Pulse Dial

Q

 

Result-Code Display

The modem can send result codes and connect messages to the computer as a result of connecting or failing to connect; establishing a data rate; and establishing error-correction and data-compression protocols. Refer to: ATV; AT\V; ATX.

 

Q0

Enable display

 

Q1

Disable display

T

 

T

 

Tone Dial

This command instructs the modem to use DTMF tone dialing.

V

 

 

Result-Code Format

Determines whether the modem sends short- or long-form messages to the communications application, indicating the connection status, rate, and mode.

 

V0

Return Numeric Code (Short Form)

 

V1

Return Text (Long Form)

X

 

Select Call-Progress Result Codes to Return

 

X0

No Carrier; Connect. Modem reports lack of a carrier signal; connection success/failure; modem dials without waiting for a dial tone

 

X1

No Carrier; Connect; Connect <rate>. Modem reports lack of a carrier signal; connection success/failure, and the computer data rate established

 

 

X2

No Carrier; Connect; Connect <rate>; No Dial Tone. Modem reports lack of a carrier signal; connection success/failure; the computer data rate established; and the lack of a dial tone

 

X3

 

No Carrier; Connect; Connect <rate>; Busy-tone. Modem reports lack of a carrier signal; connection success/failure; the computer data rate established; and the presence of a busy signal

 

 

X4

 

No Carrier; Connect; Connect <rate>; No Dial-tone; Busy-tone. Modem reports lack of a carrier signal; connection success/failure; the computer data rate established; the lack of a dial tone; and the presence of a busy signal

Z

Z

Reset Modem Parameters to Default Configuration

&C

 

DCD Control

 

&C0

Always Asserted

 

&C1

Asserted in Data Mode Only

&D

 

 

 

DTR Control

Determines how modem responds to DTR signal from DTE.

 

&D0

Ignore DTR

 

&D1

Enter Command mode when DTR transitions from asserted to de-asserted

 

&D2

Disconnect call when DTR transitions from asserted to de-asserted

 

&D3

Reset modem parameters to default configuration when DTR transitions from asserted-to-de-asserted

&F

 

Initialize modem to default factory configuration.

&G

 

Guard Tone

 

&G0

Off

 

&G1

550 Hz Guard Tone

 

&G2

1800 Hz Guard Tone

&I

 

Dial TX Level

 

&In

Level n; n = 0 to 15. Default = 9

 

&I99

Automatic Level

&P

 

Pulse Cycle

Used when the modem is instructed to pulse dial.

 

&P0

40/60 Make/Break Ratio

 

&P1

33/67 Make/Break Ratio

 

&P2

38/62 Make/Break Ratio

&R

 

CTS Control

 

&R0

Normal

 

&R1

Always On

&S

 

DSR Control

 

&S0

Always On

 

&S1

On When Modem Recognizes Remote

&T

 

Test

 

&T0

Terminate Test

 

 

&T1

 

Initiate Local Analog Loopback Test

Disconnect the telephone line from the modem line input connector before using this command.

Set S-Register 46 = 23 (ATS46=23) before executing &T1.

&V

 

Modem Status

 

&V0

Short Form Report

 

&V1

Current or Last Connection Report

 

&V2

Long Form Report

Table 1: AT and AT& Commands

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