User's Manual

H350 LGA Serials Module Hardware User Manual Page of
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5.6.2.2 Normally Open SIM Circuit Design
Reference Design:
Figure 5- 9 Normally Open SIM Interface Reference Design
Normally Open SIM:
1）Pull out SIM card, pin 7 and pin 8 are disconnected.
2）Inset SIM card, pin 7 and pin 8 are shorted.
Note:
 For better EMC performance, SIM card holder should be close to module

Filtering capacitor should be close to SIM card pin
 The interface need add ESD protection, ESD should be close to SIM card pin
 USIM_IO is already pulled up inside the module
USIM_CD support SIM hot plug, high level activated default (detect level can be changed by AT
command). If high level is detected, it means SIM card is inserted.
5.6.3 USIM Design Notice
The SIM interface and signals design is extremely important.
There are several design guidelines that must be followed: