The government said yesterday that American Telephone & Telegraph Co. was in "substantial compliance" with federal orders to end job discrimination against women and minorities.

The declaration, presented to a federal judge in Philadelphia by the Equal Employment Opportunity Commission and the Departments of Justice and Labor, brings to an end a discrimination case that already has cost the giant utility more than a quarter of a billion dollars in back pay and promotion costs.

The action yesterday also ended a pioneering chapter in the history of employes' civil rights. In the years since the AT&T case began, affirmative-action plans have become a fixture of the corporate scene.

From the beginning, the AT&T case was important as a signal to other corporations of the government's deadly serious intention to enforce a liberal interpretation of the equal employment laws. It also served as an example of the extent to which job discrimination could be corrected through federal force and specific employment targets that looked an awful lot like quotas.

The finish to the AT&T case comes just at the time the U.S. Supreme Court is considering the constitutionality of affirmative-action employment plans. The case before the court takes up a charge by a white male worker, Brian Weber, that he was illegally discriminated against by being denied a spot in a training program at Kaiser Aluminum that was geared toward minorities and women.

Both corporate and government officials involved in the AT&T case yesterday expressed satisfaction at the outcome, though there were many second thoughts voiced by each side.

Federal attorneys, while complimenting AT&T for meeting the obligations set for it, wished those obligations had been stricter. They said AT&T is still left with a number of equal employment problems.

AT&T officials, obviously proud about having improved the company's job record, were troubled by the methods used. "For this period of time, what we did was proper," said Donald E. Liebers, AT&T's equal employment opportunity director. "But it's not the way people should be treated on a continuing basis."

The progress at AT & T has had its costs. The Bell System paid more than $12 million in one-time back payments to wronged employes, and substantial promotional adjustments for thousands of others are costing the company more than $40 million a year, according to the government's report.

In addition, AT&T has had to shoulder greatly increased training expenses. Company officials also claim the utility's operating efficiency has suffered as a result of having to hire and promote workers who may sometimes not have been the best candidates for the jobs.

The government's report, prepared jointly by the Justice and Labor departments and the EEOC, lists these important employment gains at AT&T:

Women now comprise 28.5 percent of the management employes, compared with 22.4 percent in 1973 when the consent decree was signed.

In top-level management, the number of women increased from 2.1 to 6.9 percent, and in mid-level management the number rose from 11.2 to 20.7 percent.

Blacks on a system-wide basis went from 10.6 to 12.0 percent, and in management they increased from 2.3 to 5.6 percent.

Hispanic employment moved up from 2.5 to 3.9 percent overall, and from 0.7 to 2.1 percent in the management ranks.

But the report concluded that all is still not well among AT&T's work force of 980,000. "The government does not believe," the report stated. "that all equal employment opportunity problems have been remedied and forever put to rest. Problems of both an individual and systematic nature may still exist within all the companies."

In particular, government officials note that women have been slow to move into certain skilled jobs that often require strenuous work, such as climbing poles, pulling cables or dropping into manholes. In addition, minority women have made greater job strides in recent years than have minority men -- a reflection, say company officials, of the female bias of the government's standards.

Government lawyers partially excuse AT&T for some of these shortcomings, noting in the final report that the initial decree "was not intended to be the instrument" to solve all the company's equal employment problems.

Though yesterday's action releases AT&T from the court's jurisdiction, the company remains subject to the full array of the nation's equal employment laws.

"The decree put a lot of people [at AT&T] in a position where they can compete for jobs," said William Robinson, an EEOC attorney. "But they are not yet there. AT&T will have to continue to be vigilant in this regard, and we will be watching."