User's Manual

GSM/GPRS/GNSS Module Series
MC20 Hardware Design
MC20_Hardware_Design Confidential / Released 62 / 95
If the module is used as a caller, the RI would maintain high except when the URC or SMS is received.
When it is used as a receiver, the timing of RI is shown below.
Figure 33: RI Behavior as a Receiver When Voice Calling
Figure 34: RI Behavior as a Caller
Figure 35: RI Behavior When URC or SMS Received
URC
Certain URCs can trigger 120ms low level on RI. For more details, please refer to
document [1]