Rotary Dial and Thumbwheel Devices for Manually Entering Sequential Data

A rotary telephone dial and a device consisting of ten thumbwheel switches in a single array were compared in terms of user speed, accuracy, and preference. Where a completely different telephone number was used during each trail, the thumbwheel device took 20 to 60 percent longer than the rotary dial and was disliked by nine out of ten subjects. In contrast, where the successive trials involved telephone numbers with the same prefix, the thumbwheel device took 40 to 60 percent less time than the rotary dial and was preferred by eight out of ten subjects. Error rates were low and the same on both devices.