Technical information

Chapter 2: Hardware Interface Description
November 15, 2008 G24-L Module Hardware Description 25
• A 100Ω series resistor must be placed on the SIM_CLK signal line.
The resistor value may slightly change depending on the application design.
• It is recommended to design component placeholders (unpopulated) for capacitors on the
SIM_RST and SIM_DIO signal lines.
• The SIM card tray should be located, and its signals should be routed, away from any
possible EMI sources, such as the RF and digital switching signals.
• The SIM interface signals length should not exceed 100mm between the G24-L interface
connector and the SIM tray.
• The SIM clock and data signals (SIM_CLK and SIM_DIO) should be routed separately on
the application board, and preferably isolated by a surrounding ground plane.
• In case that transient suppressors (zener diodes, etc.) are used by the application on the SIM
card signals, individual package components (not arrays) with low capacitance should be
used.
• The G24-L interface does not support SIM programming through the VPP signal. This signal
should not be connected to G24-L.
• Using the SIM detection signal (SIM_PD_N) is mandatory in case that the SIM card is
accessible to the user, and may be removed during G24-L operation. To avoid damage to the
SIM or G24-L, the SIM interface signals must be deactivated before the SIM card is
mechanically removed from the SIM tray contacts. Therefore, the SIM_PD_N detection
signal must be disabled before the SIM is removed from the tray.