The PC based screening audiometer PDD-401 is used for air conductive examination of hearing system. The IEC 645-1 standard, Class Type 4 and Type 5 device in compliance to EN ISO 7029, offers 2000 Statistical distribution of hearing thresholds as a function of age. The device offers interpretation by PTA (Pure Tone Average) and by Grade of Hearing Impairment. It is system integrated with Piston spirometers and System integrated into information networks. It is regarded as Health Level 7 (USA) and Geräte Daten Träger (Germany). Offers trend analysis with unlimited patient data/result storage and fully supports pre-post examinations.