AL7020S Designer’s Guide
Doc. No. DG_7020B
Altec Electronic AG
Seite 19 / 32
3.7 External SIM Card Interface (-ES Option)
4 signals exist:
• SIMVCC: SIM power supply.
• SIMRST: reset.
• SIMCLK: clock.
• SIMDATA : I/O port.
The SIM interface controls a 3V SIM. This interface is fully compliant with GSM 11.11
recommendations concerning SIM functions. It is recommended to add Transient
Voltage Suppressor diodes on the signal connected to the SIM socket in order to
prevent any Electrostatic Discharge. TVS diodes with low capacitance (less than
10pF) have to be connected on SIMCLK and SIMDATA to avoid any disturbance of
the rising and falling edge. These types of diodes are mandatory for the Full Type
Approval. They shall be placed as close as possible to the SIM socket.
3.7.1 External SIM Card reader pins supported:
Signal
Pin number
I/O
I/O type
Description
SIMCLK 32 O 2X
SIM
Clock
SIMRST 31 O 2X
SIM
Reset
SIMDATA
30
I/O
CMOS / 3X
SIM DATA
SIMVCC 28 O SIM
Power
Supply
3.7.2 SIM socket pin description:
Signal
Pin Number
Description
VCC 1
SIMVCC
RST 2
SIMRST
CLK 3
SIMCLK
CC4
4
VCC module (Not connected)
GND 5
GROUND
VPP 6
Not
connected
I/O 7 SIMDATA
CC8
8
SIMPRES (Not connected)
1
2
3
4
5
6
7
8
SIMVCC
SIMRST
SIMCLK
GND
SIMDATA
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