T 5.95 Bugging of indoor conversations over mobile phones

Mobile phones can be used to record or listen to conversations unnoticed. In the simplest case, a mobile phone can be switched on, connected to an interested third party and inconspicuously placed in a room, for example where a meeting is being held. However, as the phone has only a limited battery life and the microphone is not designed for room surveillance, such an attempt at bugging is of only limited effect.

Through skilful selection of features and combining these with additional frills, it is possible to put a mobile phone into talk mode without this being indicated by a ringing tone or other means. For example, there is one type of phone in which the mobile phone's display can be switched off by entering a particular key combination even though a call is actually connected to the device.

However, specially manipulated mobile phones can also be used for this purpose. With these phones, it is not evident from looking at the phone that it is switched on. Here the mobile phone is used as a bugging device which can be activated from anywhere in the world over the telephone network, without this being detectable from the phone itself. Devices in which this special function is implemented using additional circuits are known. This manipulation is relatively easy to detect through visual inspection after taking the device apart or using special investigation methods. Operation of such devices is illegal in Germany.