Technical Manual

1. INTRODUCTION
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LZT 123 7607 R1B
Once a path has been set up, voice or data communication can take place.
An RS232 9-signal serial interface is available via the GT47’s 15-way high
density data connector.
This primary serial interface can be used to:
1. Control the GT47 via an external PC or micro-controller using AT
commands;
2. Send and receive data.
The GT47 supports the full set of AT commands according to GSM 07.05
and GSM 07.07. It also supports an extended set of Ericsson proprietary AT
commands to add extra functionality.
AT commands are used to operate the GT47 with a broad range of
functions including:
• configuring general parameters of the GT47
• setting up and controlling communications to and from the GSM
network
• obtaining GSM network status information
Additionally the GT47 provides a second RS232 serial interface, operating
as a 4-signal and GND interface, with hardware flow control (Rx, Tx, CTS
and RTS). This 4-signal serial interface is controllable via embedded
applications and may be used to control external accessories e.g. a GPS
receiver.
For more detail on the AT commands supported by the GT47 see “AT
Command Summary”, page 36.
1.3.8 Extended I/O Interface
The control terminal contains several general purpose, configurable, input
and output signals. Signals may be reconfigured by AT command or by
intrinsic function when using embedded applications.
• 1 analogue input
• 3 digital inputs
• 5 digital outputs
• + 4.8V DC output
In addition, 6 of the control signals on the primary RS232 interface can be
reconfigured for use as digital inputs or outputs if required.
The drivers controlling certain outputs have been designed to carry higher
currents than normal logic IOs. They can be used to activate or power
external devices, for example a switch or a relay.
A+4.8V output is available, if required, to power external devices.