Besides selling his company to SBC Communications Inc., perhaps the biggest thing that Richard Notebaert, chief executive of Ameritech Corp., did last year was to launch a new product called Privacy Manager that is intended to help people avoid unwanted calls from telemarketers. Notebaert seldom fails to mention Privacy Manager when he talks about the wonders of new telecommunications technology and urges everyone to buy the service. The service isn't especially advanced technologically, but it is a stroke of marketing genius. It requires that customers buy Caller ID and Privacy Manager, which totals about $11.50 a month added to each bill from Ameritech. When someone who phones the home of a Privacy Manager subscriber has blocked the call so that Caller ID cannot show it, the service kicks in with an interception. An automated voice asks the caller to identify himself. If he does, it puts the call through with the identification so the subscriber can decide whether to take the call. If the caller declines to identify himself, the system disconnects and the subscriber's phone never rings at all. The product is based on the assumption that pesky telemarketers block their calls, and Notebaert contends that Ameritech research has found this is the case. About 7 out of 10 unwanted calls are derailed by the product, Notebaert estimates. While Ameritech executives expected Privacy Manager sales would be healthy, acceptance by Chicago area customers has exceeded even the most optimistic projections, he said.

But like any successful product, Privacy Manager is attracting competitors, so Ameritech may have to cut charges or otherwise make its offering more attractive to keep up momentum. A small company based in Glen Cove, N.Y., Compliance Technologies Inc., last week started marketing its own service aimed at steering telemarketers away from consumers who don't want to hear from them. Customers pay $7.50 a year to enter up to two phone lines on Compliance's don't-call database. The real-time nature of the service as well as the flexibility that lets people block calls for some products while letting others through are what set this service apart from others, said David Mortman, operations director for Compliance. Other services require that names and phone numbers be sent to several companies and entered in a variety of databases, said Mortman. Compliance deals with long-distance companies that handle calls for telemarketers. So far it has signed up the fourth-largest long-distance carrier and hopes the big three will follow. Telemarketers should embrace the service, he said, because it helps them comply with various state and federal regulations that forbid unwanted telephone solicitations.