Specifications

7.2. DESIGN OPTIONS
GSM and GPRS network coverage. Combined with TCP/IP, such a system
offers the ability to upload the data to any device with internet connectivity.
This attractive attribute makes it an ideal solution for the data link. Possible
methods of delivering the captured data include:
• Dial-up modem link
• Periodic updates via SMS
• Central web- server to which nodes upload their data with customised
user-interface
• Central FTP-server to which nodes upload their data
• Periodic updates via e-mail
Key elements to consider for each solution are:
• Power consumption
• Cost and infrastructure requirements
• Feasibility
• Ease of use
• Flexibility
Bearing these constraints in mind, the following argument f ollows:
Dial-up modem links are slow, power-hungry and require a server with
connected modem and installed server software. This will need to be administered
by the user which would require them to be proficient with such systems.
Ultimately, circuit-switched-data (CSD) is an outdated, overly-complicated,
inefficient and expensive technology which is not suited to this application
(which periodically uploads small packets of data).
After consulting the four network service providers’ (Vodacom, MTN,
Cell-C and Virgin Mobile) data options, it was found that SMSs would cost
significantly more than a GPRS connection in the long term. If we assume
an average of 100 tag reads per day with each record consisting of 16bytes,
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