Meeting novel experimental needs with an Apple Pascal controlled interfacing system

In this article, we describe how to combine an inexpensive interface with an independent timing card to solve some common timing and programming problems. Problems were encountered when we tried, by modifying commercial software, to create novel programs that would accurately control events in our operant conditioning chambers. The solution was to combine a Life Science Associates (LSA) Apple Interfacing System with an Applied Engineering Timemaster II H.O. timing card. Three aspects of the solution are described: (1) LSA's interfacing hardware; (2) the Timemaster II H.O. timing card; and (3) the Pascal commands necessary to access the timing card. An example, a program to control a concurrent variable-interval schedule, shows how the timing card is used in conjunction with the interface to control and monitor experiments. The system offers many advantages over earlier researcher-built approaches and provides a flexible, accurate, and inexpensive alternative to commercial systems.