One of a series of three resource guides concerned with communication, control, and computer access for disabled and elderly individuals, the directory focuses on switches and environmental controls. The book's three chapters each cover products with the same primary function. Cross reference indexes allow access to listings of products by function, input/output feature, and by computer model. Switches are listed separately by input/output features. Typically provided for each product are an illustration, the product name, vendor, size, weight, power source, connector type, cost, and a description. The first chapter describes switches and controls including those marketed as separate devices and intended to be used with a wide range of communication or control aids. The second chapter presents environmental controls which control some other device in the person's environment including page turners, telephone dialers, and remote appliance switches. The last chapter reviews call, monitoring, and memory systems among which are special call buzzers, adaptations to hospital call systems, telephone emergency call systems, activity monitors for elderly or disabled persons, and memory aids or reminder systems. Appendixes include a list of additional sources of information, a glossary, addresses of manufacturers listed with their products, and an alphabetical listing of all products in the 3-book series. (DB)