Harry E. Blanchard

User Performance and Preference for Alphabetic Entry from 10-Key Pads: Where to Put Q and Z?

The numeric keys on the keypads of devices such as telephones and point of sale terminals have the letters of the alphabet mapped onto the digits 2-9, except for Q and Z, which are missing. The international standards bodies CCITT and ISO/TEC are standardizing the placement of letters on 10-digit keypads, and must decide where to place Q and Z. Two alternatives have been considered: placing Q and Z in alphabetic order on the 7 and 9 keys, respectively, or placing Q and Z on the 1 key. A study was conducted to determine if one of these alternatives is to be preferred on the basis of human keying performance and/or preferences. Performance differences were too small to conclude that one alternative should be preferred, however, the majority of users clearly indicated a preference for alphabetic order. A nation-wide preference and usage survey among active calling card and bank machine users revealed an overwhelming preference for the alphabetic order. Finally, a summary is given of the current status of the 10-key pad standardization process in CCLTT and ISO/TEC.

Conversational Re-Prompting in Natural Language Dialog

Natural language understanding technology has reached a level of sophistication where it can be profitably employed in interactive voice response systems in telephony. This paper describes a call routing application, where callers state a request in unconstrained, natural speech. The system then routes the call to the correct destination system or attendant. If there is a problem in understanding, then the caller must be re-prompted. This paper looks at two cases of re-prompting in the second turn of dialog based on the callers response in the first turn: (a) when a callers initial request is to speak to a real person instead of stating the reason for their call, and (b) when callers are too vague in their initial response. A strategy of conversational re-prompting is introduced which fits into the greater naturalness of the dialog, and, we show, increases the performance of the system in terms of successful fulfillment of user requests.