APPENDIX A. AT COMMANDS

 

 

 

 

 

 

 

+++

Escape Characters

Default : +

 

 

Switch the modem from Online State to Command State without

 

 

breaking the data connection. This character can be redefined by

 

 

changing the value in S Register S2.

 

 

 

AT=x

Write to Selected S Register

 

 

 

 

This command writes the value x to the currently selected S register. An

 

 

S register can be selected by using the ATSn command. All of the S-

 

 

register will return the OK response if x is a number.

 

 

 

AT?

Read Selected S Register

 

 

 

 

This command reads and displays the selected S register. An S register

 

 

can be selected by using the ATSn command.

 

 

 

ATA

Answer

 

 

 

 

 

This must be the last command entered into the command line. The

 

 

modem proceeds with the connect sequence in answer mode. The

 

 

modem will enter the connect state after exchanging carrier with the

 

 

remote modem. If no carrier is detected within a wait period specified in

 

 

register S7(default = 50 seconds), the modem will disconnect. Any

 

 

character may be entered via the DTE during the connect sequence to

 

 

abort the command.

 

 

 

ATBn *

Set ITU-T or Bell mode

Default : 0

 

 

ATB0

Selects ITU-T V.22 and V.21 standards for communication at

 

 

 

1200 and 300bps

 

 

 

 

ATB1

Selects Bell 212A and 103 standards for communication at

 

 

 

1200 and 300bps

 

 

 

ATCn

Carrier control

Default : 1

 

 

This command is included for compatibility only, and has no effect

 

 

other than returning a result code.

 

 

 

 

ATC1

Normal transmit carrier switching

 

 

 

ATDn

Dial

 

 

 

 

 

This must be the last command in a command line. ATD causes the

 

 

modem to go off-hook, dial according to the parameters entered, and

 

 

attempt to establish a connection.

 

 

 

 

If there are no parameters, then the modem goes off-hook in originate

 

 

mode without dialling a number.

 

 

 

 

Punctuation may be used for clarity. Parentheses, hyphens and spaces

 

 

are ignored. If an invalid character is entered, that character and all

 

 

subsequent characters in the dial string are ignored. The modem

 

 

truncates dial strings to 36 characters.

 

 

 

 

Parameters: 0-9 A B C D * # L P T R ! @W , ; ^ S=n

 

 

 

 

0-9

DTMF digits 0 to 9

 

 

 

 

 

 

 

ACTIVE Professional External Modem User’s Manual

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