SIM340 Hardware Design
ADC accuracy*: 12bits.
3.15 Behaviors of the RI
Table
21
: Behaviours of the RI
State
RI respond
Standby
HIGH
Voice calling
Change LOW, then:
（
1
）
Change to HIGH when establish calling.
（
2
）
Use AT command ATH, the RI pin changes to HIGH.
（
3
）
Sender hangs up, change to HIGH.
（
4
）
Change to HIGH when SMS received.
Data calling
Change LOW, then:
（
1
）
Change to HIGH when establish calling.
（
2
）
Use AT command ATH, the RI changes to HIGH.
SMS
When receive SMS, The RI will change to LOW and hold low level about
120 ms, then change to HIGH.
URC
Some URCs triggers 120ms low level on RI. For more details,
please
refer to document [10]
If the module is used as caller, the RI on the board-to-board connector will maintain high.
However, when it is used as receiver, following is timing of ring.
Power on
Ring
MO or MT
Hang up
Ring
Hang on
(talking)
MO or
MT
Hang up
Ring
RI
HIGH
LOW
Figure 32: SIM340 Services as receiver
SIM340_HD_V3.09
18.03.2009
50
Содержание SimCom SIM340
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