A model for the configuration of incoming wats lines

WearGuard is a direct marketer and retailer of uniforms and work cloths, which relies primarily on phone orders for sales. For this purpose it maintains a series of toll-free 800-number lines, known as WATS lines, to receive its incoming calls. These lines are of several types, where each type serves a different portion of the country and has a different usage fee. In this paper we determine how many of each type of WATS lines should be employed. After defining the problem more completely, we develop a queueing model to describe the system and a dynamic program to solve the configuration problem to optimality. The model has been applied to the problem by WearGuard since 1984. We present an example and examine the sensitivity of the solution to variations in various parameters. We validate the model by comparing the results of this model to other approximate models.Formerly: WearGuard, Director of Decision Support Systems, Longwater Drive, Norwell, MAmis 02061, USA