Behaviors Of The Ri - Quectel M85 Hardware Design

3.13. Behaviors Of The RI

Table 24: 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.
Voicecall
3. Calling part hangs up, RI changes to HIGH first, and changes to LOW for
4. Change to HIGH when SMS is received.
Change to LOW, then：
1. Change to HIGH when data connection is established.
2. Use ATH to hang up the data calling, RI changes to HIGH.
Datacall
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 120
SMS
ms, then changes to HIGH.
Certain URCs can trigger 120ms low level on RI. For more details, please refer to
URC
the document [1]
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 below.
HIGH
LOW
M85_Hardware_Design
120ms indicating ―NO CARRIER‖ as an URC, then changes to HIGH
120ms indicating ―NO CARRIER‖ as an URC, then changes to HIGH
RI
Idle
Figure 44: RI Behavior of Voice Calling as a Receiver
Confidential / Released
Off-hook by"ATA"
On-hook by "ATH"
SMS received
Ring
GSM/GPRS Module
M85 Hardware Design
again.
again.
64 / 92