Shielded Cabinets o enclosures
According to CCN (National Cryptological Center), TEMPEST refers to studies, investigations and control of compromising emanations relating to classified information is being transmitted, received, managed or somehow processed by electronic equipment or systems. Once these unintentional electromagnetic emissions are detected and analysed, could lead to the obtention of this information.
Furthermore, TEMPEST countermeasures are security measures intended to protect equipment and communication infrastructures against the compromise of classified information through unintentional electromagnetic emissions.
Additionally, Tempest is a NSA specification and NATO certification regarding to information systems espionage through unintentional radio, electrical, sounds or vibrations emissions. Tempest scope is from other espionage to protection equipment against this espionage, being known as EMSEC (emission security) last option.