Data Application

The quick sending mode and general mode can be set through AT + CIPQSEND command. The default mode is general mode.

AT + CIPQSEND = 0 refers to general mode; AT + CIPQSEND = 1 refers to quick sending mode.

In general mode, the active result mode "SEND OK" will be reported at the module side when the far-end receives the data sent by the module.

In quick sending mode, URC "DATA ACCEPT：< length >" will be reported at the module side whether the far-end receive the data or not. Users can query the data sending state through AT + CIPACK command.

1) Check if the port is occupied.

2) Check if the baud rate of the module, modulator-demodulator, and dial-up connection.

3) Check if the APN setting is correct.

4) Check if the stream control states of the module and the modulator-demodulator are consistent.

5) Check if the SIM is available for use.

The maximum timeout value for the SW of SIM900 series is 7 minutes. However, in practical application, if the module cannot receive acknowledgement from the far-end within 3 minutes, SIMCom recommends that users resend the data. If ACK is not received from the far-end 3 times, SIMCom suggests that users check the network status through AT + CREG, or connect and reestablish the connection with AT + CSQ or AT + CIPSHUT.

The maximum timeout value for the SW of SIM800 series is 11 minutes. In practical application, refer to 4.10.

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