TSCM (technical surveillance counter-measures)

The search covers eavesdropping devices and radio transmitters, devices that exfiltrate over mobile networks or wireless links, concealed cameras, tracking devices, interference with telephone and data cabling, and modified everyday or conference equipment. The methods used include radio spectrum analysis, non-linear junction detection, thermal imaging, systematic physical and visual inspection, checks of cabling and telephone installations, and a survey of wireless networks in the vicinity.

A sweep is not only a search for devices. Equal attention goes to weaknesses that permit eavesdropping without any planted device: acoustic leakage through walls, doors, ventilation ducts and windows, unprotected cabling, uncontrolled access to the room, and devices already present that combine a microphone with a network connection. Recommendations therefore normally include structural, organizational and procedural measures, not merely the removal of devices.

The result of a sweep is a snapshot in time. Its validity ends the moment control over access to the room ends, so sweeps are combined with an entry regime, sealing and repetition — before and after sensitive meetings and at intervals. A room used continuously for sensitive discussions requires a stricter regime than one swept once.

When a device is found, it is evidence. The first reaction should not be to remove it but to document its location and state, preserve the chain of custody and decide on further action, which may include analysis, notifying the authorities or filing a criminal complaint. Unauthorized eavesdropping on and recording of another person's communications is a criminal offense in Slovenia, so the situation is handled in a way that keeps it possible to prove.