Bell Atlantic Mobile Systems, a cellular telephone service provider, yesterday said it was introducing the first personal-use mobile-service package for $49.95 a month.

Until now, the principal customers for the mobile telephone service have been businesses rather than individuals. The system works by relaying calls from radio antennas as cars move from one place to another. Cellular phones can also be mounted inside briefcases.

The Bell Atlantic rental package offers a phone and 100 minutes of evening and weekend calling. Customers will pay 65 cents a minute for calling between 7 a.m. and 7 p.m. and will pay 15 cents a minute above the 100-minute call limit at night and on weekends, said a spokesman for the company.

"The plan is designed for people who are at work all day and need the phone for emergencies, traffic jams, etc.," said Brian Wood, a company spokesman. "It is designed for somebody with a higher usage need during the evenings and weekends." Bell Atlantic serves Washington, Baltimore, Philadelphia and Pittsburgh.

While the new service is aimed at individual consumers with disposable income, business applications for the new service might include insurance and real estate agents, trucking companies and night delivery services, he said.

Nevertheless, the service "is probably not going to be something every consumer can afford," said Wood. The function of the new package is to test the as-yet-untapped consumer market, he said.

Al Grimes, vice president of Cellular One, a Bell Atlantic competitor that provides service in Washington, Baltimore and Philadelphia, said the new service was "smoke and mirrors."

"The main reason for buying it is for business purposes," Grimes said. He predicted business customers would find little use for the package on weekends and at night, and would be "disappointed" when they discovered the 65-cent charge for peak-time use.

Even so, Cellular One plans to introduce a non-business package itself, he said.