The telecommunications systems in the greatest demand by consumers are cellular telephone and personal communication services (PCS). Both are portable methods of communication between a moving subscriber and the landline telephone system. In both services, subscribers use a portable handset to establish a connection through a cell site. Cellular telephone and PCS fraud can be divided into low-tech fraud and high-tech fraud. Subscription fraud is the least sophisticated and the most common form of fraud. Persons establish service with the use of false credentials and never pay for the service. Although the carrier eventually disconnects the service, individuals can continue to place calls from outside the home carrier's service area because of the time delay between the delivery of this roaming service and the report of the service to the home carrier. The vulnerability of a cellular or PCS network to high-tech fraud depends on the technology the carrier uses. Telecommunications fraud is costly to the industry, so carriers use various fraud- detection measures. Usually software-based, these programs attempt to identify fraudulent subscribers and cloned telephones. Carriers also institute various fraud-prevention measures to prevent a fraudulent subscriber from completing a call. These methods are usually hardware-based. With the ability to provide telephone number and location information, the odds of catching criminals and convicting them will increase. The effectiveness of this strategy will depend on the relationship between the law enforcement agency and the carrier. Investigators interested in pursuing PCS or cellular fraud cases should contact the carriers in their service areas to determine their interest in establishing liaison and providing referrals. 7 notes