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FIBOCOM L860-GL Series Hardware Guide
Page 39 of 60
3.5.2.2
N.O. SIM Card Slot
The reference circuit design for N.O. (Normally Open) SIM card slot is shown in Figure 3-16:
Figure 3-16 Reference circuit for N.O. SIM card slot
The principles of the N.O.SIM card slot are described as follows:
When the SIM card is detached, it connects an open circuit between CD and SW pins, and drives
the SIM_DETECT pin low.
When the SIM card is inserted, it connects the short circuit between CD and SW pins, and drives the
SIM_DETECT pin high.
USIM Hot-Plug
The L860 module supports the SIM card hot-plug function, which determines whether the SIM card is
inserted or detached by detecting the SIM_DETECT pin state of the SIM card slot.
The SIM card hot-plug function can be configured by “AT+MSMPD” command, and the description for AT
command is shown in the following table:
AT Command Hot-plug Detection Function Description
AT+MSMPD=1 Enable
Default value, the SIM card hot-plug detection function is
enabled.
The module can detect whether the SIM card is inserted or not
through the SIM_DETECT pin state.
AT+MSMPD=0 Disable
The SIM card hot-plug detect function is disabled.
The module reads the SIM card when starting up, and the
SIM_DETECT status will not be detected.
After the SIM card hot-plug detection function is enabled, the module detects that the SIM card is inserted
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