D-Link DMI-128ESU User Manual

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D-LINK ISDN TA DMI-128ESU+ 
28 
6. AT COMMAND 
6.1 Description of AT Command 
Hayes command set is a standard for Hayes modem commands for its Smart modem 300. Most 
modem manufactures adopted this command set in order to have Hayes compatible. The command 
set used by the Smart modem 300, as well as most modems or TAs today (with a few additional 
new advanced commands), is known as the AT command set. AT stands for attention, and is 
placed in front of actual content of command so that the TA knows what follows is an command 
directed at the modem or TA. With the exception of some “A/” and “+++” command, “AT” 
command is the process to place command to the TA.  
Different modems or TA’s may have slightly different command sets, but generally speaking, most 
of the TAs follow the standard set by Hayes. 
6.1.1 AT Command  
When you connect terminal equipment (like PC) with the TA, after typing AT command ending 
with [ENTER] key, TA will process the command and then return the result code to the terminal 
equipment. Each AT command must starts with “AT” and end with [ENTER] key  (with the 
exception of “A/” and “+++” commands). 
 
Command Format 
The following is the format of AT command: 
 
AT 
Command Value Command Value CR LF 
 
Result code has two styles (Verbose and Numeric). The following are their formats: 
CR LF 
Result 
code(Verbose) 
CR LF 
Result code (Numeric)  CR 
 
S register  
The S register is used to store the settings including  
 
auto answer mode 
 
escape sequence character 
 
V.110 connect speed ..... etc.