The European Committee for Electrotechnical Standardization (CENELEC) standardized the way the SAR level is measured in the year 2001. All manufacturers use this system to measure the SAR levels of their devices.
Manufacturers check to ensure that their cell phones comply with the exposure limit of two watts per kilogram (body weight) (2W/kg) and publish the maximum SAR values measured in their operating guides. The provisions governing the SAR measurement system are described in international standard IEC/EN 62209.
The measuring system consists of a plastic object shaped like a head. It contains a special fluid, which has properties that cause electromagnetic fields to propagate in it in the same way as in human head tissue. The cell or smart phone which is being tested and which is transmitting at full power is held to the 'ear' on the plastic head. A measuring probe records the distribution of SAR in the liquid inside the head and calculates the maximum SAR level.
The SAR values published by Deutsche Telekom correspond with the maximum levels stipulated by the EU standard.