4. The apparatus defined in claim 3 further comprising means, responsive to the termination of said prerecorded messages, for preventing the next pre-recorded message from being played until after a pause in the respondent's response exceeds said first predetermined duration.
3. Apparatus for carrying on a programmed telephone conversation with a respondent via a telephone line adapted to carry a voice communication of the respondent, the apparatus including means having a plurality of pre-recorded messages which are playable in sequence in response to a corresponding response from the respondent, and further comprising: interface means for coupling said apparatus to the telephone line; a speech detector coupled to the interface unit to monitor the voice communication; first timer means, coupled to said speech detector, for timing a pause exceeding a first predetermined duration in said voice communication of the respondent; means responsive to said first timer means for causing the playing of the next pre-recorded message after said first predetermined duration; second timer means, coupled to the speech detector, for timing an absence of said voice communication of the respondent exceeding a second predetermined duration greater than said first predetermined duration, subsequent to the playing of a pre-recorded message; and means responsive to said second timer means for altering the course of said programmed telephone conversation.