User's Manual

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1.4.9 USIM
The UIM contains parameters necessary for the WWAN device’s operation in a wireless
wide area network radio environment. The UIM signals are described in the following
paragraphs for M.2 add-in cards that support the off-card UIM interface.
(1) USIM card socket
It is recommended to take electrostatic discharge (ESD) protection measures near the USIM
card socket. The USIM socket should be placed near the NGFF interface (<100 mm),
because a long circuit may impact signal quality.
(2) UIM-PWR
UIM_PWR power supply can supply 1.8 V and 2.85 V power to UIM card and auto detects
follow SIM card type
(3) SIM Detect
This signal is used to detect the insertion and removal of a SIM device in the SIM socket.
With a Normal Short SIM Card connector, PUSH-PUSH type, the detect switch is normally
shorted to ground when no SIM card is inserted. When the SIM is inserted, the
SIM_DETECT will transition from logic 0 to logic 1 state. The rising edge will indicate
insertion of the SIM card. When the SIM is pulled out, the SIM_DETECT will transition from
logic1 to logic 0. This falling edge will indicates the pulling out of the SIM card. The M.2
module monitoring this signal will treat the rising/falling edge or the actual logic state as an
interrupt, that when triggered, the module will act accordingly.