AT&T has started testing a free ad-supported directory assistance service that provides callers with business telephone numbers and general listings, the U.S. telephone giant announced last week.

The new service is available in Bakersfield, California; Columbus, Ohio; and Oklahoma City, Oklahoma, as part of a controlled trial. It can be accessed by dialing 1-800-YellowPages in any of these markets.

Customers who dial the number will hear short audio advertisements related to their inquiries before their call is connected to the requested business.

This represents a significant advertising opportunity for AT&T Yellow Pages customers, who can promote special offers to customers asking for their specific number, or run audio ads to customers requesting their category of business. AT&T is also offering sponsorship ads, which run on a general basis to inform users that the service is being sponsored by a certain company or brand name.

Increasingly, our customers are calling directory assistance when they don`t have a phone book handy or can`t jump online, said AT&T`s senior vice president of Diversified Businesses, David Huntley, in a statement. We`re developing AT&T 1-800-YellowPages to be the consumer`s audio Yellow Pages that gives them free access to local and nationwide business listing information from any phone, 24/7.

At the same time, we want to help businesses reach consumers at a key moment when consumers are in need of a service and are ready to make a purchasing decision, Huntley went on to explain. This trial period will allow us to later roll out a service that best meets our consumer and business customer needs.