With TL-03305, the BSI provides regularly updated lists of shielded devices, which are classified into the four classes "Level A" device, as well as "Zone 1", "Zone 2" and "Zone 3 device" according to their emission characteristics as defined by the National Zoning Model of Emission Security.

Property / building zone	Up to and including GEHEIM (SECRET)	Up to and including VS-VERTRAULICH (CLASSIFIED -- CONFIDENTIAL)
Table 1: Minimum requirements for emission characteristics of TEMPEST device
Zone 0: (>8) to 20 m	"Level A" device	"Zone 1 device"
Zone 1: >20 to 100 m	"Zone 1 device"	"Zone 2 device"
Zone 2: >100 to 1000 m	"Zone 2 device"	"Zone 3 device"
Zone 3: >1000 m	"Zone 3 device"	"Zone 3 device"

"Level A" devices are special in this respect because their emissions must meet very high requirements (i.e. very low emission levels) both in the free space and cable-bound. This means that "Level A" equipment can also be used in controlled areas that have both low free-space attenuation and low conducted attenuation. However, the usually high hardening effort is then also noticeably reflected in the device price.

On the other hand, the requirements for the emission properties of "Zone 3 device" are so low that they are already fulfilled by many unmodified devices, i.e. commercial off-the-shelf (COTS) devices.

In any case, before any CI processing begins, each individual device, regardless of its classification, must have passed an emission test (survey measurement method). Usually, these obligatory emission tests are carried out directly after manufacture by the respective TEMPEST device manufacturer.