There are plenty of options for customers who want to make purchases from Christian Book Distributors (CBD), a discount seller of religious books in Peabody, Mass. They may mail in their orders, call an operator, or dial a special number to place orders with an automated system.

CBD's automated system, installed in 1990, uses interactive voice-response technology. Callers use their telephone keypads to enter item numbers, the customer-identification number from their catalogs, and credit-card information. A recorded voice confirms the information they enter and generates a packing list for CBD's warehouse staff.

Cofounder Ray Hendrickson says that because each order processed by a live operator costs CBD from $1.50 to $2, the $40,000 system paid for itself in less than six months. About 10% of the company's phone-in customers choose the automated system.

There is a trade-off, Hendrickson admits. The orders taken by machine are, on average, 7% smaller than those taken by live operators, who often recommend additional purchases to customers.