Examines the costs of information centers using voice-grade telephone lines to access recorded messages for biomedical personnel. Projected utilization is estimated as a function of physician population, number of messages available, and advertising promotion. The demand estimates, ranging from 464,600 to 884,400 calls per year, are national extrapolations from the University of Wisconsin Dial Access Center experience. Telephone line rental charges are a major portion of costs. Sufficient lines must be available so that no more than 5 percent of the calls at peak usage hours will be blocked. The total annual operating cost for a single national center ranges from $673,000 to $936,000, with cost per call between $1.06 and $1.45. This includes personnel, supplies, line charges, facilities rental, and promotion and evaluation costs. Single centers are generally more economical than multiple centers. (See also RM-6204.) 65 pp.