Specifications

7.5. RELIABILITY
7.4.9 Command Processing and Device Configuration
The command interface is in the form of a terminal window across RS232, or
via a combination of SMS and email. The operator can configure the system
by issuing commands such as
set time 16:29:49 23/10/06, or,
set email receiver joe [e-mail].
Appendix C.2 lists all available commands. To perform these configuration
changes on the prototype using a serial connection, a 5V – RS232 level
translator is necessary as this interface is not included with PCB v1.0. For
this purpose a MAX232 IC suffices. Future PCB versions will include this
interface and a standard DB9 serial connector. Upon successful receipt of
a command, the module responds with status report listing the new device
configuration.
It is necessary to program the initial configuration using the serial connection
as the GSM module is unable to start at this point due to a lack of the
SIM PIN configuration. SIM authentication is thus not possible until the
EEPROM device settings have been saved. Once configured, however, all
commands may be SMSed to the unit as if it were connected directly via
serial cable. The command is processed when the unit next initiates a GSM
connection (either because the upload threshold was reached or because the
operator invoked an upload manually by pressing the upload button).
7.5 Reliability
It is very important that the device be reliable. Because the unit will be
installed in the field and administered remotely, the device needs to be self-
diagnosing and should be able to remotely restart itself automatically should
a fault o ccur. To this end, full use of the microprocessor’s reliability features
have been made. Also, the hardware has been carefully designed to ensure
that the device will recover from a depleted backup battery when mains
power is restored. The software is modular which allows for simple trouble-
shooting, code correction or expansion.
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