The Mobile Phone Module is the only part of the system that is visible to the field personnel. It is the software that appears on their mobile phone, presented as an easy-to-fill questionnaire.

Behind the scenes, the Mobile Phone Module runs Java Micro Edition (Java ME), which means it can be ported to any mobile phone that runs Java. However, the software is optimized for the Nokia E71 mobile phone because it has a full QWERTY keypad, an in-built GPS chip for accurate location data, a large screen for ease of use, a camera, and long battery life.

Crucially, the Mobile Phone Module has a smart connectivity component. When the field personnel send data back to the headquarters, the phone will first try to use the data network. If there isn’t a mobile data network but there is a mobile voice network, the mobile client will send it by text message (SMS). This process is totally automated and invisible to the person sending the interview results.