Cellular Technical Services and GTE Wireless Sign Agreement to deploy CTS's Blackbird Platform and PreTect Anti-Cloning System.

SEATTLE--(BUSINESS WIRE)--April 30, 1997--Cellular Technical Services Company, Inc. (Nasdaq/NM Symbol: CTSC) ("CTS"), a leading provider of real-time information management systems for the wireless communications industry, today announced that it has signed a master purchase and license agreement with GTE's wireless subsidiary under which CTS will supply GTE Wireless with the CTS Blackbird(R) Platform and PreTect(TM) wireless fraud prevention system.

The contract calls for initial deployment of the CTS system in GTE Wireless's Virginia markets and complements an existing agreement between CTS and GTE Wireless's California markets. The new agreement also includes GTE Wireless's participation in CTS's No Clone Zone(SM) service which provides real-time roaming fraud prevention service to cellular service providers across the nation.

"The Blackbird(R) Platform product line is an excellent extension to our extensive anti-fraud arsenal," said Jeff Schaulin, Manager - Customer Assurance Operations, GTE Wireless. "It will significantly enhance our ability to stay several steps ahead of the criminals and to help protect our customers both in their home markets and when they roam."

Bill Zollner, CTS President and COO, said: "GTE Wireless is one of the largest and fastest growing wireless providers in the country. We are very pleased that they've chosen the Blackbird(R) Platform and PreTect(TM) application to help stop cloning fraud. Also, GTE Wireless's participation in our No Clone Zone(SM) service will further expand our network's roaming coverage in markets throughout the country."

Cellular fraud occurs when a criminal uses sophisticated equipment to steal a legitimate customer's phone number and Electronic Serial Number (ESN) as they are being transmitted over a wireless network. These same numbers are then reprogrammed into another cellular phone 'cloned' for illegal phone service use.

Fortunately, every cellular phone has a unique set of electronic characteristics, just as every person has a unique fingerprint. The PreTect(TM) application on the Blackbird(R) Platform uses patented signal processing, or RF fingerprinting technology to accurately distinguish between legitimate customers and counterfeit users on a pre-call basis. This system captures information from the cellular phone call at the cell site, before it enters the service provider's system, and compares it to validation data. PreTect(TM) can then automatically intercept and shut down a call if a proper match is not made. The No Clone Zone(SM) service provides seamless real-time roaming fraud prevention between markets using the Blackbird(R) Platform and PreTect(TM) application.

GTE Wireless provides wireless voice, paging and data services and products to more than 4 million customers in 73 metropolitan and 52 rural markets nationwide. CTS provides technologically advanced solutions for the wireless industry to rapidly and cost-effectively grow their businesses. The company's Blackbird(R) Platform fraud prevention product line is slamming the door on cloners in the largest markets across the United States including Los Angeles, New York, San Francisco, Chicago, Detroit, Boston, Atlanta, Milwaukee, Philadelphia, Baltimore, Washington D.C. and San Diego

Blackbird is a registered trademark; PreTect is a trademark; and No Clone Zone is a service mark of Cellular Technical Services Company, Inc.

CONTACT: Company Contact:

Joseph D. Pititto

Director, Investor Relations 

516/887-0727