Behaviors Of The Ri - Quectel M35 User Manual

3.11.
When using PCM interface, RI pin can be used as PCM_CLK.
Table 18: Behaviors of the RI
State RI Response
Standby HIGH
Change to LOW, then:
1. Change to HIGH when call is established.
2. Use ATH to hang up the call, RI changes to HIGH.
Voice Calling
3. Calling part hangs up, RI changes to HIGH first, and changes to LOW for
4. Change to HIGH when SMS is received.
When a new SMS comes, the RI changes to LOW and holds low level for about
SMS
120ms, then changes to HIGH.
Certain URCs can trigger 120ms low level on RI. For more details, please refer to
URC
the document [1].
NOTE
If URC of SMS is disabled, the RI will not change.
If the module is used as a caller, the RI would maintain high except the URC or SMS is received. On the
other hand, when it is used as a receiver, the timing of the RI is shown as below.
HIGH
LOW
M35_User_Manual

Behaviors of The RI

120ms indicating ―NO CARRIER‖ as an URC, then changes to HIGH again.
RI
Idle Ring
Figure 36: RI Behavior of Voice Calling as a Receiver
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M35 User Manual
Off-hook by"ATA"
On-hook by "ATH"
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