How to Enter Serial AT Command Mode

1.The product of the USR have AT command mode. If you forget your setting or make a wrong setting, you can enter AT command mode, inquire or change the setting.
2.The diagram of enter AT command is as follow.

Serial AT Command Mode-  diagram of enter AT command
3.We use the USR-TCP232-TEST software to send serial command. You can use your own serial software or MCU send command to our module.

AT Figure 2
4.Configure the serial parameters. Open the serial port.
Serial AT Command Mode-onfigure the serial parameters
5.Send +++ to serial. If you add a SPACE or ENTER, that will not return the correct character.
Serial AT Command Mode, send +++ to serial
6.If you give a correct command, the module will return an 'a'
Serial AT Command Mode, give the correct command
7.When you receive an 'a', you should send an 'a' at once(in 3 seconds). You can not add any SPACE or ENTER either.
Serial AT Command Mode, add any SPACE or ENTER
8.The module will return +Ok if the module enter the AT command mode.
The module will return +Ok if the module enter the AT command mode.
9.Now you can send AT command to the module, but you should add an ENTER after your command.
you should add an ENTER after your command