Audio Interfaces - SimCom SIM5215 Hardware Design

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Figure 20: RI behaviour in NULL Modem
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 21: RI behaviour in FULL Modem
To comply with RS-232 protocol, the RS-232 level shifter chip should be used to connect
SIM5215&SIM5216 to the RS-232-C interface. In this connection, the TTL level and RS-232 level are
converted mutually. SIMCom recommends that user uses the SP3238ECA chip with a full modem. For
more information please refers to the RS-232 chip datasheet.
Note: SIM5215&SIM5216 supports the communication rate: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600,
115200, 230400, 460800, 921600, 3200000, 3686400, 4000000bps. Default rate is 115200bps.
3.4

Audio Interfaces

SIM5215&SIM5216 provides three analog signal outputs and two analog input. MIC1P/N and HP_MICP
is used as microphone, HPL/R, EAR1P/N and SPK_P/N are used as audio output. Regarding audio
parameters configuration, please refer to the ATC manual.
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SIM5215&SIM5216_Hardware Design_V2.02 2012-08-31