Xylem iCE3 GPRS Variant - Manual (Page 7)

GPRS iCE 3 , V1.30 User Guide
iQuest (NZ) Ltd - PO Box 15169, Hamilton, New Zealand Tel: +64 7 857 0810 Fax: +64 7 857 0811 Email: [email protected] 3
2.4 Key Features
2.4.1 Terminal Configuration
All configuration and set-up parameters are modified via a standard ASCII terminal connected to the RS232
serial interface. This means that the user can configure the device without needing to have specialised
configuration software installed on their computer specifically for this purpose.
2.4.2 Wireless Internet Connectivity (GPRS)
Wireless Internet connectivity is provided via the on-board dual-band GPRS modem. Through this interface,
data packets can be transferred to and from the host (RS232) port. To facilitate GPRS connectivity, a
suitably activated SIM card must be installed in the device. It is also necessary to program the unit with
appropriate settings via a terminal connected to the host (RS232) serial interface.
The iCE
3
communicates over a GPRS network using UDP protocol via a single data port. The device
supports ASCII and binary communication to a wide range of iQuest and third party equipment.
2.4.3 Static and Dynamic IP addressing
The iCE 3 supports both static (fixed) and dynamic IP address modes. Whether the mode is static or dynamic
is set by the service provider and the SIM card supplied by them.
Static IP addressing allows the iCE
3
to work with any mix of software or device, as each end of the GPRS
link knows the IP address of the other end. However, this mode usually requires a dedicated APN or else an
additional ongoing cost for a static IP on a wider area network.
Dynamic IP addressing requires that HydroTel™ is installed at the remote (base) location. In this mode, the
iCE
3
initiates the connection, typically via the Internet and sends a special call-in packet to the base.
HydroTel™ then captures the IP address and port that have been allocated to the iCE
3
for that session and
uses them for all ongoing communication with the host device attached to the iCE
3.
Using this mode is
described in detail in Section 5.
The advantage of dynamic IP addressing is the ability to have low cost IP connectivity to any device
supported by HydroTel™. This can be achieved by a simple Internet connection via a local service provider.
The intelligence of the iCE
3
manages the GPRS session establishment and maintenance, meaning that the
host device does not need any special intelligence of its own. However, the host device might be
programmed to force a GPRS connection by issuing a simple command (AT^IGOL), perhaps in responses to
an alarm condition. This feature assumes the device supports the issuing of serial strings on demand.
2.4.4 Gateway Communication
Provision has been made for support for System DO  gateway functionality between the GPRS network and
the RS232 serial interface. This enables the unit to be used as a bridge between the wide area GSM
network and a localised network of iQuest devices. By connecting a data radio to the iCE
3
's serial port, it is
possible to communicate with several devices in a multi-drop radio network from the GPRS network.
The gateway transparently redirects System DO
 packets received via GPRS from address 0 back out the
serial port if they are not destined for the iCE
3
. Conversely, packets received on the serial port from any
address and directed to address zero (0) will be transparently redirected onto the GPRS network.