Evaluation of a Proposed Alternative to the AN/TTC-39 Signaling Tones System.

This experiment assessed the potential impact of signaling tones simplification on users of the ANTTC-39 communications system. A significant 33 percent to 50 percent reduction in learning time for full feature use was achieved over previously tested alternatives which are currently recommended by the manufacturer. The need to reduce overall system complexity was determined through both empirical data analysis and subjective means such as questionnaires. Identification was made of problem tones and tone situations responsible for a significant proportion of subscriber difficulty, and suggestions for remediation were offered. Author