User's Manual

Smart Machine Smart Decision
SIM7100A_User Manual_V1.01 2014-12-11
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If Full Modem is used to establish communication between devices, the pin “RI” is another operation
status. Initially it keeps high, when a voice call or CSD call comes, the pin “RI” will change to low for
about 5900ms, then it will return to high level for 100ms. It will repeat this procedure until this call is
answered or hung up.
Figure 14: RI behaviour in FULL Modem
3.3.2 Design Guide
The application circuit is in the following figures.
Figure 15: UART Full modem
Figure 16: UART Null modem