USR-DR504-E User Manual
Jinan USR IOT Technology Limited
Tech Support: h.usriot.com
31
the mobile phone to the module. After receiving it, the module will return the response information as shown in the
figure below:
Diagram 3.1.5-1 SMS Command
3.1.6. Command format
AT command is "question and answer" command, divided into "question" and "answer" two parts. "Question"
means that the device sends an AT command to DR504-E, and "answer" means that DR504-E sends a reply to the
device.
Note: characters in instructions are case-insensitive.
3. 1. 6. 1 Symbol description
Figure 9 Symbol Description
Symbol name
Implication
<>
The content is necessary items
[]
The content is non-essential items
{}
The content is a string with special meaning
~
Parameter range , e. g. A~B. Parameter ’s range is from A to B
CMD
Command code
OP
The operator
PARA
Parameters
CR
Enter key in ASCII, 0X0D in hex
LF
Line break in ASCII,0X0A in hex
Form3.1.6.1-1 Symbol Description
3. 1. 6. 2 The queation format in command
Command string: <AT+>[CMD][OP][PARA]<CR>
Figure 10 symbol description
Command code
Implication
Necessary or not