The system described, VISC, has as its aim the acquisition and subsequent digitization of monodimensional cardiotocographic signals. These signals can originate in any type of hospital cardiotocographic register, as well as in a book of uterine activity (UA) or fetal heart rate (FHR) signals. VISC consists of a set of algorithms to identify the fetal heart rate signal, although it can be used with minor corrections to work on any continuous curve. Some of the problems that may arise, such as signal loss and presence of noise, are discussed to illustrate the proposed method. The program is integrated into a wider environment, whose main nucleus is the NST-EXPERT expert system, for the diagnosis of fetal well-being, the recommendation of therapeutical plans and the prognosis of immediate neonatal states.