SimCom SIM800 User Manual

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SIM800_Hardware Design_V1.10 30 2018-08-13
UART1_TXD
UART1_
RXD
UART
1_RTS
UART1_CTS
UART1_DTR
UART1_DCD
UART1_RI
TXD
RXD
RTS
CTS
DTR
DCD
RING
Serial Port
Serial Port
Module(DCE)
Customer(DTE)
GND GND
Figure 19: Connection of the serial port
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.
1K
5.6K
RXD
TXD
RTS
CTS
GPIO
GPIO
EINT
DTE
(3.3V)
5.6K
5.6K
1K
1K
1K
1K
1K
1K
Module
UART1_TXD
UART1_RXD
UART1_RTS
UART1_CTS
UART1_DTR
UART1_DCD
UART1_RI
GND
GND
Figure 20: Level converting by resistor
If the voltage of UART is 3V or3.3V, user also can use following reference circuits:
UART1_TXD
RXD
Module DTE
TXD
UART1_RXD
VDD_
EXT
10K
10K
GND
GND
Figure 21: Isolation circuit by diodes

SimCom SIM800 Specifications

General

Brand	SimCom
Model	SIM800
Category	Control Unit
Language	English