With three young children at home, Patricia Allen wanted to give up the two-hour daily commute from her home in Upper Marlboro to her job in downtown Washington, so in April 1972 she applied to work as a secretary for the Prince George's county government. For the next year, Allen says, she called repeatedly to ask about job openings.

She was annoyed when she was told none were available. And she filed suit after a white neighbor told Allen that she had been hired during the period when Allen was asking for a job.

Joined by another plaintiff, Sylvester Vaughns, Jr., a county employe and former chairman of the Prince George's NAACP, Allen charges that the county's personnel practices consistently discriminate against the hiring and promotion of blacks, whether the county intends this or not. The suit also contends that when blacks do win employment or promotion in county jobs, they are paid as much as $1,500 less a year than white workers of comparable education or experience.

Today, Allen's and Vaughns' lawsuit goes to trial in Baltimore before U.S. District Judge Alexander Harvey II and a decision in their favor could cost the county millions in back pay and damages.

"If you're talking about an across-the-board judgment against the county, you could certainly be in the millions of dollars," said Prince George's County Attorney Robert Ostrom.

The case has become a class action suit representing most of the county's 883 black employes and potentially hundreds of "minimally qualified" black applicants who were denied county jobs. It is the second major discrimination case pending in federal court against Prince George's; the other is a massive school desegregation suit reopened this fall by the NAACP.

According to pretrial papers filed last week, the county will argue that its personnel policies have never discriminated against blacks. Lawyers from the firm of Arent, Fox, Kinter, Plotkin and Kahn, representing Prince George's, will point to what they call an "extraordinary" affirmative action effort to recruit and promote blacks since the first home rule adminstration of former county executive William Gullett in 1970.

In the decade since Gullett took office, the black population in the county has more than doubled, from about 16 percent in 1970 to about 37 percent today. According to the county's personnel office, blacksnow make up 23 percent of county employes.

Allen and Vaughns, represented by the firm of Arnold and Porter, will attempt to show that blacks are underrepresented in county jobs, given their availability in the area labor pool. County lawyers will present their own statistical evidence in an effort to prove blacks are hired in proportion to the number of applications submitted by blacks.

The county also will try to show that Allen and Vaughns did not receive the job or promotion that each wanted because of factors that had nothing to do with race.

"We are confident that we are not going to get hit between the eyeballs," said Ostrom last week. "We are a responsible government, and if we truly believed that there was an adverse impact on blacks , we would have done something about that."

But the plaintiffs, preparing to attend the three-week trial after years of delay, are still angry about what they see as unfair treatment and are equally certain that the court will take their side.

"If it took me 20 years, I'd follow it," said Allen, 36, now a GS-11 administrative assistant for the Federal Commnications Commission who earns more than three times what she would have as a county secretary in 1972.

Her lawyers are asking for at least $12,639 in damages, the difference between what she would have earned had the county hired her between April, 1972 and August, 1975, when she got another job with comparable pay. But Allen says it is not the money that is important.

"I knew that there wasn't a job down there in my field I wasn't qualified for," she said. "I can make a typewriter sing. I can make a typewriter talk to you. Initially the suit was for me, now it's for all the black people who have been discriminated against or passed over for promotion."

Vaughns was a party to the original school desegregation suit in Prince George's, but has asked to be dropped from the reopened case. He is not giving up on Allen's suit, however, which he joined in 1975 when he was downgraded from a grade 30 to a grade 27 position during a reorganization of his county department. He charges that a white employe in his department was transferred at the same time without any loss of pay.

Although he still works for the county, in the office of Licenses and Permits, Vaughns says that he still gets angry "everytime I get my paycheck."