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L811-EB Hardware User Manual Page 29 of 47
Figure 3-12 Reference Circuit for N.C. SIM Card Slot
The principles of the N.C. SIM card slot are described as follows:
When the SIM card is detached, it connects the short circuit between CD and SW pins, and drives the
SIM1_CD pin low.
When the SIM card is inserted, it connects an open circuit between CD and SW pins, and drives the
SIM1_CD pin high.
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 3-13:
Figure 3-13 Reference Circuit for N.O. SIM Card Slot
The principle description for N.O. SIM card slot is shown in the following:
When the SIM card is detached, it connects an open circuit between CD and SW pins, and drives the
SIM1_CD pin low.
When the SIM card is inserted, it connects the short circuit between CD and SW pins, and drives the
SIM1_CD pin high.