Huawei MG323 manual Audio Interface, 12External circuit for 32 Ω handsets/16 Ω headsets

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HUAWEI MG323 GSM M2M Module
Hardware Guide	Description of the Application Interfaces

To meet the requirements of 3GPP TS 51.010-1 protocols and electromagnetic compatibility (EMC) authentication, the SIM card socket should be placed near the B2B connector interface (it is recommended that the PCB circuit connecting the B2B connector interface and the SIM card socket not exceed 100 mm), because a long circuit may lead to wave distortion, thus affecting signal quality.

It is recommended that you wrap the area adjacent to the SIM_CLK and

SIM_DATA signal wires with a ground wire. The GND pin of the SIM card socket and the GND pin of the SIM card must be well connected to the power GND pin supplying power to the MG323 module.

A 0.1 µF capacitor or a 0.22 µF capacitor is placed between the VSIM and GND pins in parallel. Three 33 pF capacitors are placed respectively between the SIM_DATA and GND pins, the SIM_RST and GND pins, and the SIM_CLK and GND pins in parallel to filter interference from RF signals.

You do not need to pull the SIM_DATA pin up during design as a 15 kΩ resistor is used to connect the SIM_DATA pin to the VSIM pin.

It is recommended to take electrostatic discharge (ESD) protection measures near the SIM card socket. The TVS diode with Vrwm of 5 V and junction capacitance less than 10 pF must be placed as close as possible to the SIM socket, and the Ground pin of the ESD protection component is well connected to the power Ground pin that supplies power to the MG323 module.

3.8Audio Interface

The MG323 module provides two types of audio interfaces: one is for handsets, the other is for headsets. The audio interfaces of the MG323 module support input from handset microphones and headset microphones, and provide output that supports 32

Ωhandsets and 16 Ω headsets. Differential signal lines are recommended for the microphone interface and the speaker interface. Single-ended signal lines are not recommended. The reception gain can be adjusted by using software.

Figure 3-12External circuit for 32 Ω handsets/16 Ω headsets

HUAWEI Module (Modem)

INTEAR_P/

ferrite bead

EXTEAR_P

100 pF

INTEAR_N/

ferrite bead

EXTEAR_N

33 pF

33 pF

ESD protection

+

-

Speaker

	Issue 06 (2013-06-13)	Huawei Proprietary and Confidential	27
		Copyright © Huawei Technologies Co., Ltd.

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Contents Hardware Guide Issue DateNo Warranty Creation About This DocumentHistory Version Date Chapter DescriptionsVersion Date Chapter Descriptions Updated .8 Audio Interface Updated -3 RecommendedSpecifications of the antenna interface Contents Electrical and Reliability Features Overview IntroductionFunction Overview Feature DescriptionOverall Description About This ChapterGprs Gprs Class DRX=2DRX=5 DRX=9 SMSCircuit Block Diagram Application Block Diagram2Circuit block diagram of the MG323 module Description of the Application Interfaces B2B Connector InterfaceMin Tpy Max Pin Pin Name Description DC Characteristics NormalLedstatus ResetTermon UART1DCDVbat Power InterfaceOverview VIODCE Pin No Signal Name DescriptionVbat Interface GND VcoinPower-On and Power-Off Time Sequence Vcoin InterfaceVIO Interface Power-On Time Sequence Pin for controlling power-on and power-offPin for resetting the hardware Signal Control Interface Power-Off Time SequenceReset Pin for network status LED Input Signal Control PinsOutput Signal Control Pin Application DeviceWorking or Network Status Uart Interface Pin No Signal Name Description Feature DirectionDCE data set DCE is ready DCE to DTE Ready Circuit Recommended for the Uart InterfaceDCE receive DTE transmits DTE to DCE Data Serial data DCE data DTE is ready DTE to DCE Terminal readyReset signal of the SIM card Clock signal of the SIM cardPower supply of the SIM card Data signal of the SIM cardCircuit Recommended for the SIM Card Interface Ground signal of the SIM cardAudio Interface 12External circuit for 32 Ω handsets/16 Ω headsets13External circuit for the microphone interface Antenna Interface Antenna InstallationEnvironmental Type Material Condition Coaxial Cable and RF ConnectorHuawei MG323 GSM M2M Module Hardware Guide Antenna Interface Uplink frequency range GSM 824 849 MHz RF Specifications of the Antenna InterfaceSpecification Minimum Typical Maximum Unit Value ESD Protection for the Antenna InterfaceSpecification Minimum Typical Maximum Unit Value Polarization Linear polarization Pattern Omnidirectional Specifications of the Antenna InterfaceExtreme Working Conditions Electrical and Reliability FeaturesSymbol Specification Minimum Value Maximum Value Unit External power voltageElectrical Criteria of Application Interfaces Operating and Storage Temperatures and HumiditySpecification Minimum Value Maximum Value Unit Pin No Signal NameThan 3.3 Function Signal Name Waveform Remarks LevelPower supply Voltage great drop. The Vbat power voltageLedstatu Pins 41, 43, 45, 47, and 49 are power GND ExternalPower pin VBAT=0UART1 UART1RD UART1RINUART1DSR UART1RTS UART1DTR UART1CTS UART1DCD Parameter Minimum Value Typical Value Maximum Value Unit Power Supply FeaturesInput Power Supply Working CurrentWorking Mode Typical value Unit Remark ConfigurationBand Typical Unit Test Condition Standard Reliability FeaturesConfiguration Value Up/1 Down 123Test Condition Standard ESD Features ESD Test Standard Contact Discharge Air DischargeEN61000-4-2 ±4 kV ±8 kV Mechanical Specifications DimensionsDimensions L x W x H 35 mm x 32.5 mm x 3.05 mm 1Dimensions of the MG323 module unit mm Dimensions of the B2B ConnectorModel Stacking HRS Number Height mm 5Structure fixing hole MG323 Module Installation Description6MG323 module installation 7Machine screw dimensions Specification Selection for Fasteners8Nut dimensions 1Circuits of typical interfaces in the MG323 module Appendix a Circuits of Typical InterfacesAcronym or Abbreviation Expansion Appendix B Acronyms and AbbreviationsRTC PbcchPCB PDU

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