Table 1: AT and AT& Commands

Command

Option

Description

 

 

 

T

T

Tone Dial

 

 

This command instructs the modem to use DTMF tone

 

 

dialing.

 

 

Example: ATDT5554678.

 

 

This command uses DTMF tone Dialing to dial the number

 

 

5554678

V

 

Result-Code Format

 

 

Determines whether the modem sends short- or ling-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 sig-

 

 

nal; connection success/failure; modem dials without wait-

 

 

ing 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

 

 

 

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Motorola SM56 manual Tone Dial, Result-Code Format, Select Call-Progress Result Codes to Return, DCD Control, DTR Control