Installation Instructions

Table Of Contents
L508 Hardware Design
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18 USIM_RST SIM reset control
USIM card reset signal, output by the
module, support 1.8v/3v dual voltage range.
19 USIM_CLK SIM clock
USIM card clock signal, output by the
module, supports 1.8V/3V dual voltage
range.
53 USIM_CD USIM hot-plug detection Only 1.8 v Range is supported.
Note: L508 SIM Card Channel Signals support dual-level mode, the module will automatically adapt
to the type of External Sim card jump.
4.5.2 Electrical characteristics
The USIM Card Signal Unit, on the line near the USIM card seat, please note the need to add ESD
protection devices when designing.
In order to meet the requirements of 3GPP TS 51.010-1 protocol and EMC certification, it is
recommended that the seat of the USIM card should be placed near the interface of the module USIM
card, so as to avoid the serious distortion of the waveform caused by the long line and the influence
of the Signal integrity. USIM and USIM signal routing recommendations packet earth protection. A
100nF and a 33pF capacitor are connected in parallel between the GND and the SIM_VDD. A 22pF
capacitor is connected in parallel between the USIM, USIM, USIM and the GND to filter out
interference from the RF signal. USIM, USIM, USIM series 22 resistance to enhance static protection.
4.5.3 USIM card interface application