There are two user interface modes between WizFi250 and User-System.
Command mode is the default communication mode and all AT Commands can be used only at this mode. Through AT Commands, users can do 'WiFi Configuration', 'Sending/Receiving Data', 'Managing System', and so on. WizFi250 treats all received data from users as AT command. If all received data follows the correct command format, WizFi250 processes it and returns a proper response to user.
Data mode, on the other hand, is the mode which passes data of application layers to peer devices directly, without AT commands or any other interventions. It can be considered as a black box which passes all USART input to USART output directly. Its concept is simple but to enter this mode, Users need to set the environment properly through AT Commands.
Users can enter Data mode by writing '1' at '<DataMode>' parameter of AT+SCON command. Make sure that there are no open sockets before performing this, because Data mode works with one socket only. (So if you try to open another socket in data mode it will fail). If the socket of Data mode is closed, the mode will be changed to Command mode automatically so users can input AT Commands. If users set AT+SCON command as service with data mode option and save the profile, Data mode will be started when WiFi is joined, so the user does not need to set environments anymore. If the system boots or reboots at that time, WiFi Join will also be started automatically. Users can exit from data mode temporally by entering '+++' in a row (Wait for a second until [OK] response show up). Any AT Command can be entered during Data mode except AT+SCON command. If you want to return to data mode again, you just need to enter AT+SDATA. If you want to exit Data mode completely, close the socket by using 'AT+SMGMT=0' or 'AT+SMGMT=ALL'.
In Command mode, you can make more than one socket, and you can send/receive data through opened sockets at the same time by using AT Command. You can send data to specific socket opened through AT+SSEND command and receive data with information header which informs you on the socket number, the peer address and the received data length.