SIM Tech SimCom SIM5218E, Проектирование аппаратного обеспечения

Страница: 37 / 71

SIM5218E Hardware Design
SIM5218E_ Hardware Design_V1.06 2012.09.21
36
EP output signal in mV
rms. @ 0dBm0, 1024
Hz, no load (default
gain) / @ 3.14 dBm0 508mV 2.1Vpp 407mV 1.68Vpp 1220mV 4.5Vpp
Sidetone gain at default
settings 25.0dB 25.3 dB - ∞ dB
3.8.5.4 Adjust the sound level by AT+CVLVL
There are two adjustable amplifiers on audio signal output path: <rxVol>, <rxGain>. Four AT
commands are provided for tune them..
<rxVol>: AT+CLVL, AT+CVLVL,AT+CRXVOL
<rxGain>: AT+CRXGAIN
AT+CRXVOL is used for fine tuning for <rxVol>. AT+CLVL and AT+CVLVL are used for
coarse tuning for <rxVol>. AT+CVLVL changes the sound level values of the command CLVL.
Now we provide 5 levels for each audio channel. The level 0 is muted and it can not be changed
by CVLVL. Levels 1 to 4 are supported to change the value of sound level. CVLVL command
could let user change these four levels. The bigger the number presents the louder the voice. And
the range of each level is -5000 to 5000.
NOTE: This command influences digital volume of output signal after speech decoder. Please
check the reference document [1] for detailed information of each AT command.
3.9 USIM card interface
3.9.1 USIM card application
User can use AT Command to get information in USIM card. For more information, please refer to
document [1]
.
The universal subscriber identification module (USIM) is a smart card for UMTS/GSM cellular
applications. The USIM provides the required subscription information to allow the mobile
equipment to attach to a GSM or UMTS network. The USIM also provides the subscriber's
verification procedures as well as authentication methods for network authentication during the
attach procedures. The USIM card can be inserted into any UMTS/GSM USIM equipped handset,
allowing the user to receive or make calls, and receive other subscribed services from any USIM
equipped handset, thus enabling more handset independence for the user.
Both 1.8V and 3.0V SIM Cards are supported.
The SIM interface is powered from an internal regulator in the module having nominal voltage
2.8V. All pins reset as outputs driving low. Logic levels are as described in the table below .