Energy economy in mobile devices is becoming an increasingly important factor as the devices become more advanced and rich in features. A large part of the energy footprint of a mobile device comes from the wireless communication module, and even more so as the amount of traffic increases. In this paper we study the energy footprint of a mobile broadband hardware module, and how it is affected by software, by performing systematic power consumption measurements. We show that there are several cases where the software does not properly take into account the effect that data communication has on the power consumption. This opens up for potential energy savings by creating better applications that are aware of the energy characteristics of the communication layer.