AT setup software download address:
https://www.pusr.com/download/WIFI/USR-WIFI-AT%20Command%20Software.zip
http://www.pusr.com/download/software/USR-TCP232-Test%20V1.4.exe
Open the serial port, send “+++”(Without line breaks) from the serial port, then will receive the "a" returned by the device. Reply an "a" to the device within 3S, and will receive "+ok" , which indicates that the device has entered AT command mode.
Send AT+RELD (with a line break) from the serial port to restore the parameter settings of USR-TCP232-T2.