Human Factors Engineering Studies of the Design and Use of Pushbutton Telephone Sets

Specifically, we would like to know how pushbutton design influences user speed, accuracy and preference in keying telephone numbers. What design specifications will maximize these three quantities, and how critical is it to achieve these maxima? Also, what other factors influence user information processing in keying telephone numbers? For example: How does performance improve with practice? Does it matter how the number to be keyed is displayed? And are there systematic procedures t h a t users follow in keying numbers? The design features are discussed in Section I I I and fall into four groups: (a) key arrangement, (b) force-displacement characteristics, (c) 995 996 T I I E BELL SYSTEM T E C H N I C A L J O U R N A L , J U L Y 1 9 0 0 button top design and (d) central office considerations. Observations concerning other factors in keying behavior are presented in Section IV.