Technical information

Chapter 2: Hardware Interface Description
November 15, 2008 G24-L Module Hardware Description 45
Antenna Detection
The G24-L incorporates an internal antenna detection circuit, which senses the physical
connection and removal of an antenna or antenna circuit on the G24-L antenna connector. The
antenna detection state is reported to the application through the ANT_DET output signal, and
may also be queried by the ATS97 command.
The detection circuit senses DC resistance to ground on the G24-L antenna connector.
A DC resistance below 100kohm (+
10%) is defined as a valid antenna connection, and the
ANT_DET output signal is set high.
GPRS Detection
The GPRS output signal indicates the network GPRS connection status. When G24-L is
connected to a GPRS network, this signal is enabled. When G24-L is not connected to the GPRS
network this signal is disabled.
Transmission Indicator
The TXEN_N output signal indicates when G24-L is transmitting over the GSM network. This
signal follows the G24-L GSM transmit bursts. This signal is set low during transmission burst,
and set high when no transmission is in progress.
Figure 2-25 shows the TXEN_N operation.
Figure 2-25: TXEN_N Operation
General Purpose I/O
The G24-L incorporates 8 general purpose IO signals for the user application. Each GPIO signal
may be configured and controlled by AT command. These signals may be used to control or set
external application circuits, or to receive indications from the external application.