SimCom SIM5300E Hardware Design page 44

The pin is changed to low. When any of the following events occur, the pin will
be changed to high:
Voice call
（1）Establish the call
（2）Hang up the call
The pin is changed to low. When any of the following events occur, the pin will
be changed to high:
Data call
（1）Establish the call
（2）Hang up the call
The pin is changed to low, and kept low for 120ms when a SMS is received.
SMS
Then it is changed to high.
The pin is changed to low, and kept low for 120ms when some URCs are
URC reported. Then it is changed to high. For more details, please refer to
document [3].
The behavior of the RI pin is shown in the following figure when the module is used as a receiver.
HIGH
LOW
HIGH
LOW
SIM5300E_Hardware_Design_V1.02
RI
Idle
Figure 33: RI behavior of voice calling as a receiver
RI
Idle
Figure 34: RI behavior of data calling as a receiver
Establish the call
Hang up the call
Ring
Establish the call
Hang up the call
Ring
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