GSM / GPRS communication module

The GSM/GPRS communication module is part of a system that can be controlled remotely. 
Specially for systems that are not easily connected to a LAN, this may be a good alternative.
The module operates as a mobile phone, and thus requires a SIM card. A data-only SIM card will be sufficient.

Currently, well over a 1000 units like this are in operation.

The module is configured that attacks from the internet are fully blocked. Hackers will not be able to tamper with the normal operation of the device.

Communication is done to a dedicated internet server. This server (software) collects all data in a database, from which the data are presented to the user with a web-based application.