AL7020S, AL7024S Designer’s Guide
Doc. No. DG_7024E 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
SIMDAT
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