Sim Interface - Nokia 3555 Service Manual

RM-257; RM-270; RM-277
System Module

SIM interface

The device has one SIM (Subscriber Identification Module) interface. It is only accessible if battery is removed.
The SIM interface consists of an internal interface between RAP and EM ASIC (N2200), and of an external
interface between N2200 and SIM contacts.
The SIM IF is shown in the following figure:
Figure 24 SIM interface
The EM ASIC handles the detection of the SIM card. The detection method is based in the BSI line. Because of
the location of the SIM card, removing the battery causes a quick power down of the SIM IF.
The SIM interface supports both 1.8 V and 3.0 V SIM cards. The SIM interface voltage is first 1.8 V when the
SIM card is inserted, and if the card does not respond to the ATR a 3 V interface voltage is used.
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