User's Manual

Table Of Contents
M80 Hardware Design
M80_HD_V1.2 - 68 -
SMS
When a new SMS comes, the RI changes to LOW and holds low level for
about 120 ms, then changes to HIGH.
URC
Certain URCs can trigger 120ms low level on RI. For more details, please
refer to 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.
RI
Idle Ring
Off-hook by
ATA. On-hook
by ATH. SMS
received.
HIGH
LOW
Figure 41: RI behavior of voice calling as a receiver
RI
Idle Ring
Data calling establish.
On-hook by
ATH. SMS
received
HIGH
LOW
Figure 42: RI behavior of data calling as a receiver
RI
Idle Calling
On-hook
Talking
HIGH
LOW
Idle
Figure 43: RI behavior as a caller