Telephone Voice Interfaces on the Cheap
Thomas Hornstein · 1997
Introduction Telephone-based information services have been introduced in the last decade. The interaction between the machine and the user was based on the telephone and its key pad using touch-tone (DTMF 1 ) signals. This technique is fairly efficient since it is simple and people are used to seeing a similar interface on other devices like automatic seller machines etc. Unfortunately the distribution of DTMF based telephones is still not homogeneous in most countries. In some areas DTMF dialling is not yet supported. In many countries - particularly in Europe - people often keep using their old pulse-dialling telephone. Additionally ISDN has been introduced as a third standard. One way of building interactive voice applications is to support the various communication standards. Another way is to be independent of the communication standard by supporting voice input. Supporting various communication standards raises several problems in the case of pulse detect