GSM/GPRS Module Series
M35 User Manual
M35_User_Manual Confidential / Released 57 / 85
3.11. Behaviors of The RI
When using PCM interface, RI pin can be used as PCM_CLK.
Table 18: Behaviors of the RI
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.
RI
Idle Ring
Off-hook by“ATA”
On-hook by “ATH”
HIGH
LOW
Figure 36: RI Behavior of Voice Calling as a Receiver
Change to LOW, then:
1. Change to HIGH when call is established.
2. Use ATH to hang up the call, RI changes to HIGH.
3. Calling part hangs up, RI changes to HIGH first, and changes to LOW for
120ms indicating ―NO CARRIER‖ as an URC, then changes to HIGH again.
4. Change to HIGH when SMS is received.
When a new SMS comes, the RI changes to LOW and holds low level for about
120ms, then changes to HIGH.
Certain URCs can trigger 120ms low level on RI. For more details, please refer to
the document [1].
To Next Page
Loading...
Need help?
General
