Sim800 hardware design v1.05

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Figure 11: Power on/down module using button
The power on timing is illustrated as following figure.
Figure 12: Timing of power on module
When power on procedure is completed, SIM800 will send following URC to indicate that the module is ready to
operate at fixed baud rate.
RDY
This URC does not appear when autobauding function is active.
Note: User can use AT command “AT+IPR=x” to set a fixed baud rate and save the configuration to
non-volatile flash memory. After the configuration is saved as fixed baud rate, the Code “RDY” should be
received from the serial port every time when SIM800 is powered on. For details, please refer to the chapter
“AT+IPR” in document [1].
4.2.2. Power down SIM800
SIM800 will be powered down in the following situations:
z Normal power down procedure: power down SIM800 by the PWRKEY pin.
z Normal power down procedure: power down SIM800 by AT command “AT+CPOWD=1”.
SIM800_Hardware Design_V1.05 23 2014-03-25