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H350 for M2M LGA Series Hardware User Manual Page
5.4.2 USB Interface Application.............................................................................................................. 29
5.5 UART Interface.................................................................................................................................. 30
5.5.1 UART Interface Description........................................................................................................... 30
5.5.2 UART Interface Application............................................................................................................31
5.5.3 Ring Indication................................................................................................................................. 32
5.6 USIM Interface................................................................................................................................... 32
5.6.1 USIM Pins......................................................................................................................................... 32
5.6.2 USIM Interface Design....................................................................................................................33
5.6.2.1 “Normal Closed”SIM Card Circuit Design............................................................................... 33
5.6.2.2 “Normally Open” SIM Circuit Design........................................................................................ 33
5.6.3 Points for Attention in USIM Design............................................................................................. 34
5.6.4 USIM Hot-Plugging..........................................................................................................................35
5.6.4.1 Hardware Connection.................................................................................................................35
5.6.4.2 Software Settings........................................................................................................................ 35
5.7 Digital Audio........................................................................................................................................36
5.7.1 I2S...................................................................................................................................................... 36
5.7.2 I2C...................................................................................................................................................... 36
5.7.3 PCM Port Description..................................................................................................................... 37
5.8 ADC Interface..................................................................................................................................... 37
5.9 Other Interfaces................................................................................................................................. 37
6 Electrical and Environmental Features...............................................................................38
6.1 Electrical Features.............................................................................................................................38
6.2 Environmental Features....................................................................................................................38
7 RF Interface................................................................................................................................ 39
7.1 Operating Frequency Band.............................................................................................................. 39
7.1.1 Frequency Range of Antenna....................................................................................................... 39
7.2 RF PCB Design..................................................................................................................................39
7.2.1 Wiring Principle................................................................................................................................ 39
7.2.2 Impedance Design...........................................................................................................................39
7.3 Antenna Design..................................................................................................................................40
7.3.1 Main Antenna Design Requirements........................................................................................... 40
7.3.1.1 Antenna efficiency.......................................................................................................................40
7.3.1.2 S11 or VSWR...............................................................................................................................40
7.3.1.3 Polarization...................................................................................................................................40