Technical information

Chapter 2: Hardware Interface Description
November 15, 2008 G24-L Module Hardware Description 23
USB Interface
G24-L incorporates a standard Universal Serial Bus (USB) interface.
The G24-L USB electrical interface and protocol conform to the USB 1.1 full-speed
specifications. G24-L is defined as a USB device on the USB bus and does not support hub or
host functionality.
USB may be used for standard communications with G24-L, as done through the UART
interface.
Important: When USB is active, G24's low power mode cannot be operated.
The USB interface signals are shown in Figure 2-12.
Figure 2-12: USB Interface Signals
SIM Interface
The G24-L incorporates a SIM interface, which conforms to the GSM 11.11 and GSM 11.12
standards, that are based on the ISO/IEC 7816 standard. These standards define the electrical,
signaling and protocol specifications of a GSM SIM card.
G24-L does not incorporate an on-board SIM card tray for SIM placement. The SIM must be
located on the user application board, external to the G24-L. The G24-L SIM interface includes
all the necessary signals, which are routed to the interface connector, for a direct and complete
connection to an external SIM.
G24-L supports dynamic detection of the SIM card, through a dedicated SIM detection signal.
G24-L will detect a SIM card insertion or removal upon power up or during operation by the
transitions on the SIM_PD_N signal.