Calls made from telephone terminals T1-Tn via a telephone network C are handled within a receiving station D by processing systems P1-Pn that by means of automated voice messages prompt the callers through an interactive sequence (Fig 3) to operate their telephone push-buttons 14 to signal digital data to the station D. Digital data received from each caller and derived otherwise from his call, is stored in a processor-­memory cell C1 (Figs 2 and 4) and, according to the processor operating format selected, gives specific identification of the caller, health data, and call sequence-order or time, together with processor-derived data which the caller is prompted to signal back to the processor for confirmatory purposes. Selection of format, and with it the particular processor PR1-PRn used, depends upon the number called, and may alternatively relate to telephone-order purchasing (Fig 5), participation in a lottery, or participation in a TV auction, gameshow (Fig 7) or opinion-poll. The caller is first checked for qualification to participate - this may depend upon entry of a one-time key signal by the caller - and after data gathering, processing of the data, for example to isolate a subset of callers or analyze it statistically, is carried out.