T 5.13 Eavesdropping of rooms

In general two different types of unauthorised bugging of rooms have to be distinguished. In the first type, the threat is directly represented by the terminal. In this case particularly intelligent terminals with installed microphones, such as answering machines, ISDN cards, or multimedia PCs are affected. Terminals of this kind can, assuming the relevant functions are installed, be activated via the public network to switch on the installed microphones. A well-known example of this is the so-called "baby-watch function" of answering machines (c.f. 8.3 Answering machine).

The second type is to make use of the PBX system itself in connection with appropriately equipped terminals. This threat arises from the abuse of the "voice calling" user facility in conjunction with the "handsfree conversing" option. This function, of an intercom switching centre with simplex transmission if applied in this way, can, under certain circumstances, also beused for the bugging of a room.