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FIBOCOM NL668-AM Hardware User Manual
Page 33 of 62
3.5.2.2 SIM card slot without detection signal
SIM card slot without detection signal, and USIM_ PRESENCE pin remains floating.
Figure 3-13 USIM/SIM Interface without Detection Signal Reference Design Diagram
3.5.3 USIM hot plug
NL668-AM SIM card supports hot plug function. It determines the insertion and removal of SIM card on
the slot by detecting the USIM_ PRESENCE pin state to support hot plug function.
The SIM card hot plug function can be configured by the “AT+MSMPD” command, and the AT commands
are shown in the following table:
AT command
SIM card hot plug
detection
Function description
AT+MSMPD=1
Enabled
Default, SIM card hot plug detection is enabled
The module detects whether the SIM card is inserted
through the USIM_PRESENCE pin state
AT+MSMPD=0
Disabled
SIM card hot plug detection function is disabled
The module reads the SIM card when the device starts,
and does not detect the USIM_PRESENCE state
Table 3-11SIM Card Hot Plug Function Configured AT Commands
After enabled the hot plug detection function of the SIM card, when USIM_PRESENCE is in high level,
the module will detect the SIM card insertion and then execute the initialization program of the SIM card.
After reading the SIM card information, the module will register network. When the USIM_PRESENCE is
in low level, the module detects that the SIM card is removed, then it will not read the SIM card.
