We designed an electronic device to monitor calling behavior in male crickets. The device and its associated software can record to disk the activity of as many as 16 individuals simultaneously. The data recorded contain detailed information about the temporal structure of each individual's calls. The temporal resolution achieved with an ordinary PC is good enough to detect and record the occurrence of every pulse of sound from each cricket. The resulting data files are efficient and compact, and so the system is appropriate for experiments lasting many days. (C) 2003 Elsevier B.V. All rights reserved.