1. Around 2001, Stethographics introduced PC-based software which enabled a phonocardiograph, graphic representation of cardiologic and pulmonologic sounds to be generated, and interpreted according to related algorithms.

2. Phonocardiograph Recorder, Long Term, ECG, Portable (Holter Monitor) Enuresis alarm (conditioned response) Stimulator, (photo-evoked response) Infrared thermometer Audiometer Likewise there is a corollary to Rule 10 which is similar to that of Rule 9.