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Figure 41: 50 keys reference circuit
Note
：
Do not change the 20KΩ resistor in the diagram.
Customer could cascade a less than 1K resistor to enhance
the ESD performance, the connection diagram is as
following:
Figure 42: Keypad reference circuit
Whether using a 5*5 keys or 5*5*2 keys, the module can also detect the two buttons pressed. But when using a
5*5*2 button, the
same row, column two buttons at the same time can not be detected when pressed,
as shown
below:
Figure 43: Keypad detected
SIM800H&SIM800L_Hardware Design_V2.02 45
2015-07-27
