Reproduction forbidden without Fibocom Wireless Inc. written authorization - All Rights Reserved.
L831-EAU-01 Hardware User Manual Page
The L831-EAU module supports the SIM card hot-plugging function, which determines whether the SIM
card is inserted or detached by detecting the SIM_DETECT pin state of the SIM card slot.
The module detects that the SIM card is inserted when the SIM_DETECT pin is high, then executes the
initialization program and finish the network registration after reading the SIM card information. When the
SIM_DETECT pin is low, the module determines that the SIM card is detached and does not read the SIM
By default, SIM_DETECT is active-high.
The SIM card circuit design shall meet the EMC standards and ESD requirements with the improved
capability to resist interference, to ensure that the SIM card can work stably. The following guidelines
should be noted in case of design:
The SIM card slot placement should near the module as close as possible, and away from the
RF antenna, DC/DC power supply, clock signal lines, and other strong interference sources.
The SIM card slot with a metal shielding housing can improve the anti-interference ability.
The trace length between the SIM card slot and the module should not exceed 100mm, or it
could reduce the signal quality.
The UIM_CLK and UIM_DATA signal lines should be isolated by GND to avoid crosstalk
interference. If it is difficult for the layout, the whole SIM signal lines should be wrapped with
The filter capacitors and ESD devices for SIM card signals should be placed near to the SIM
card slot, and the ESD devices with 22~33pF capacitance should be used.
The L831-EAU module provides three signals to indicate the operating status of the module, and the
status indicator pins as shown in the following table:
System status LED, drain
output.
To Next Page
Loading...
