Uim Card; How The Uim Card Works; Uim Card Troubleshooting - Nokia 2255 Baseband Description And Troubleshooting

Nokia Customer Care

UIM Card

How the UIM Card Works

The Nokia 2255 supports two types of UIM cards that work at 1.8V and 3.0V. When the
mobile terminal is switched on with a UIM card, the UPP sends a 1.8V signal to the UIM
card and waits for the UIM card's response and identification. After a wait period, if
there is no answer from the UIM card, the mobile terminal will send another signal at
1.8V. In this case UEMC acts as a level shifter and raises the signal to 3.0V. If there is still
no response, the mobile terminal will not allow access. If there is a response, then the
mobile terminal powers up.
SIM
From Battery
type contact

UIM Card Troubleshooting

When troubleshooting UIM cards, make these common checks (see
Figure 24):
• Check Vsim 1.8V or 3.0V. Vsim comes from UEMC and goes through the SIM ESD
protection chip. Check for bad or damaged solder joints. Replace chips if
necessary.
ISSUE 1 10/2005
UEMC GND
SIMIF Block
SIMData
SIMClk
SIMRst
VSIM
BSI
Figure 22: UIM Card Block Diagram
©2005 Nokia Corporation
Baseband Description and Troubleshooting
Data
SIMClk
SIMIO
UEME Dig.
Logic
Company Confidential
2255 (RM-97)
GND
UPP
Data
SIMClk
SIMIO
UIF Block
UEMInt
CBusDa
CBusEnX
CBusClk
Figure 23 and
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