The differential adapter for conductive lines in the speech range of frequencies (DAPL 031) is intended for use together with ST 031 "Piranha" and ST 031P.
DAPL 031 ensures:
 the detection of furtive data acquisition means that use conductive lines for signal transmission;
High sensitivity of the device and a symmetrical adapter input make it possible to reveal:
 signals from active and passive (non equipped with power supply) microphones;
 microphone modulation from office and home equipment (TV's, VCR's, hi-fis etc.); security and fire alarms, etc., in the conductive line.