SIM800L datasheet(30/73 Pages) SIMCOM

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1200, 2400, 4800, 9600, 19200, 38400, 57600 and 115200bps

The default setting is autobauding.

Autobauding allows SIM800H&SIM800L to automatically detect the baud rate of the host device. Pay more

attention to the following requirements:

Synchronization between DTE and DCE:

When DCE powers on with autobauding enabled, it is recommended to send "AT" or "at" or "aT" or "At"

to synchronize the baud rate, until DTE receives the "OK" response, which means DTE and DCE are

correctly synchronized. For more information please refer to AT command "AT+IPR".

Restrictions of autobauding operation:

The DTE serial port must be set at 8 data bits, no parity and 1 stop bit.

The URC such as "RDY", "+CFUN: 1" and "+CPIN: READY” will not be reported.

Note: Customer can use AT command “AT+IPR=x” to set a fixed baud rate and the setting will be saved to non-volatile flash

memory automatically. After the configuration is set as fixed baud rate, the URC such as "RDY", "+CFUN: 1" and "+CPIN:

READY” will be reported when SIM800H&SIM800L is powered on

4.5.2

Serial Interfaces

The following figure shows the connection between module and client (DTE).

Figure 20: Connection of the serial interfaces

If the voltage of UART is 3.3V, the following reference circuits are recommended. If the voltage is 3.0V, please

change the resistors in the following figure from 5.6K to 14K.

SIM800H&SIM800L_Hardware Design_V2.02

2015-07-27

SIM800L データシート(PDF) 30 Page - SIMCom