EC20（一）——AT指令
AT+CSQ ：Signal Quality Report， 查询信号强度；
AT+CGMM ： Request Model Identification， 查询模式ID；
AT+GMM： 和AT+CGMM 完全相同；
AT+IFC ：Set TE-TA Local Data Flow Control， 设置串口数据流
eg: “AT+IFC=0,0\r\n” , RTS与CTS均不开启。
AT&D：Set DTR Function Mode， 设置DTR
eg: “AT&D0\r\n” , 忽略DTR状态。
AT+CMEE： Error Message Format， 设置错误信息样式
The command controls the format of error result codes: ERROR, error numbers or verbose messages as
+CME ERROR:
| eg: AT+CMEE=2 ，Enable error result code with verbose (string)，用长字符串使能返回结果码。
AT+QCCID ：Show ICCID，查看SIM卡的IDeg:
|
AT+GSN ：Request International Mobile Equipment Identity (IMEI)，查询IMEI。作用和AT+CGSN完全一样.
ATE ：Set Command Echo Mode， 设置是否回应。
The command controls whether or not the module echoes characters received from TE during AT command mode.
AT+CPIN ：Enter PIN， 键入PIN码
The command is used to enter a password or query whether or not the module requires a password which
is necessary before it can be operated. The password may be (U)SIM PIN, (U)SIM PUK, PH-SIM PIN, etc.
eg:
//Enter PIN
AT+CPIN?
+CPIN: SIM PIN //Queried PIN code is locked
OK
AT+CPIN=1234 //Enter PIN
OK
+CPIN: READY
AT+CPIN? //PIN has already been entered
+CPIN: READY
OK
//Enter PUK and PIN
AT+CPIN?
+CPIN: SIM PUK //Queried PUK code is locked
OK
AT+CPIN="26601934","1234" //Enter PUK and new PIN password
OK
+CPIN: READY
AT+CPIN?
+CPIN: READY //PUK has already been entered
OKAT+IPR ：Set TE-TA Fixed Local Rate， 设置波特率
The command is used to query and set the baud rate of the UART. The default baud rate value (
eg:
AT+IPR=115200 //Set fixed baud rate to 115200bps.
OK
AT&W //Store current setting, that is, the serial communication speed is
115200bps after restarting module
OK
AT+IPR?
+IPR: 115200
OK
AT+IPR=115200;&W //Set fixed baud rate to 115200bps and store current setting
OKAT+CREG ：Network Registration Status，网络注册状态。
The Read Command returns the network registration status. The Write Command sets whether or not to
present URC。
eg：
//In Non-CDMA mode
AT+CREG=1
OK
+CREG: 1 //URC reports that ME has registered on network
AT+CREG=2 //Activate extended URC mode
OK
+CREG: 1,"D509","80D413D",2 //URC reports that operator has found location area code and
cell ID
//In CDMA mode
AT+CREG=1
OK
+CREG: 1 //URC reports that ME has registered on network
AT+CREG=2 //Activate extended URC mode
OK
AT+CREG?
+CREG: 2,1,"3747","A23C2",100 //Query the system ID, network ID and BTS ID of CDMA
network
OKATS0 ：Set Number of Rings before Automatically Answering Call。
The command controls automatic answering mode for the incoming calls。
【注意】：If
ATS0=3 //Set three rings before automatically answering a call
OK
RING //A call is coming
RING
RING //Automatically answering the call after the three ringsAT+QCFG ：Extended Configuration Setting。
The command is used to query and configure various settings of UE。
其中：AT+QCFG="risignaltype" ：RI Signal Output Carrier。
The command specifies the RI (ring indicator) signal output carrier.
参考：
Quectel_EC25&EC21_GNSS_AT_Commands_Manual_V1.0