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FIBOCOM NL668-LA Series Hardware Guide
Page 33 of 61
AT Command (U)SIM Card Hot Plug Detection Function Description
AT+MSMPD=1 Enabled
(U)SIM card hot plug detection is enabled by
default.
The module determines the insertion and removal of
(U)SIM card by detect the USIM_ PRESENCE pin
state
AT+MSMPD=0 Disabled
(U)SIM card hot plug detection function is disabled
The module read the (U)SIM card when module
power on, and does not detect the
USIM_PRESENCE state
After enabled the hot plug detection function of the (U)SIM card, if USIM_PRESENCE is in high level, the
module will detect the (U)SIM card insertion and execute card initialization program. After reading the
(U)SIM card information, the module will register network. When the USIM_PRESENCE is in low level,
the module detects (U)SIM card is removed, and it will not read the (U)SIM card.
Note:
The USIM_PRESENCE pin active high by default, and can be switched to active low by AT
command.
Table 5-8 USIM_PRESENCE
effective level switched
AT Command
Function Description
AT+GTSET=” SIMPHASE”,1
Default, high level detect
AT+GTSET=” SIMPHASE”,0
Low level detect
5.3.4 (U)SIM Design Requirements
(U)SIM card circuit design shall meet EMC standards and ESD requirements, and at the same time, shall
improve anti-interference ability to ensure that the (U)SIM card can work stably. The design needs to
strictly observe the following rules:
(U)SIM card connector is placed as close to the module as possible, away from the RF antenna,
DCDC power, clock signal lines and other strong interference sources;
Adopt the (U)SIM card connector with metal shield shell to improve anti-interference ability;
The length of cable from the module to the (U)SIM card connector shall not exceed 100mm. Longer
cable reduces signal quality.
