Late Wednesday afternoon, phone company supervisors came to Pamela Carey's third-floor office at Chesapeake & Potomac Telephone Co. headquarters and delivered the bad news: Carey and about 35 coworkers, some with as many as 15 years' experience, had been declared "surplus" workers and faced layoffs.

"They just said 'You are being surplused' and that they would place us in another job if they could. But the emphasis was on the if," Carey said. "It looks like it's going to be the unemployment line or the soup line."

What is happening to Carey and hundreds of her C&P colleagues in the District, Maryland, Virginia and West Virginia is part of the revolutionary change in the telecommunications industry brought on by the historic breakup of American Telephone & Telegraph Co. last year, and by the rapid pace of automation.

Those dramatic changes will translate to a loss of up to 726 jobs this year at C&P -- and tens of thousands nationwide -- and they will create an extended period of uncertainty and anxiety for many thousands of phone company workers who previously thought their jobs in a monopoly business were among the most secure in America.

Since the breakup of AT&T into 22 operating companies on Jan. 1, 1984, much concern has been raised about the impact of divestiture on the quality of phone service and on the financial health of Ma Bell and her seven regional Bell offshoots. But less attention has been paid to the impact on many of the nearly 1 million people who work for telephone companies nationwide.

The Communications Workers of America, which represents more than 700,000 unionized telecommunications workers, estimates that more than 35,000 people have been laid off from regional operating companies. AT&T, which now provides long-distance service, has announced plans to reduce its work force by 11,000 -- although most of those job cuts will come via attrition rather than layoff. In addition, many employes have been forced to relocate to keep their jobs or have lost seniority because of job classification changes.

"There is a lot of insecurity and anxiety, and a lot of times you don't know how many jobs you will lose, and you don't know what to tell people," said James Pappas, a CWA local vice president in the District.

According to C&P, the new wave of cutbacks will not be implemented until June and will not hit all the "surplus" workers because many may be relocated or trained for other jobs, and because retirements may open slots. C&P's regional parent firm, Bell Atlantic, has cut its 80,000-person work force by 2,000 since divestiture, and it plans reductions of 10,000 in the next five years. C&P cut 150 jobs in the District in 1984 and more than 300 jobs in the other jurisdictions by layoffs and attrition.

"It is our intent to try to relocate or find new jobs for all these people," said C&P spokesman R.W. Chamberlin, "We can't tell you how many people will be laid off or terminated. It could be one or none . . . . It could be more."

C&P notified the union on Dec. 6 that 726 jobs were to become "surplus" in 1985, and the word is now trickling down to departments within the company that particular jobs are being eliminated and workers displaced.

That uncertainty weighs heavily on the affected workers. "I didn't sleep at all last night, and I don't think anyone did," Carey said the day after she learned she was "surplused." Carey, 23, who has been a clerk-typist at C&P for four years, is a graduate of the District's Eastern High School. She was laid off from the Labor Department in the Reagan administration's reduction in force in 1981 and came to C&P after a difficult period of unemployment, she said. "But I thought this job was going to really last."

When AT&T was broken up, many Washington area employes, like their counterparts elsewhere, were given the choice of working for the new AT&T or staying with regional phone companies such as C&P. "I figured it was best to stay close to home. I guess I was wrong," said Carey, who said she considers her chances of surviving at C&P slim because of her low seniority.

In Carey's case, her several dozen coworkers are part of a 167-job reduction created by C&P's conversion to a so-called "paperless" and fully computerized system of taking customer orders, Chamberlin said. Workers who previously wrote up work orders for other employes to process will instead enter those orders directly into a central computer system, he said.

That system is one of several, designated by various company acronyms such as INFORM, TREAT and ACE, that are designed to improve efficiency and cut jobs as part of reorganization of C&P operations.

The incentive to cut back on expenses at operating companies such as C&P has grown since divestiture because C&P's parent company, Bell Atlantic, is facing competition for the first time and is seeking to maximize profit for expansion into new ventures, said Edwin Lewinski, a CWA regional official.

"I don't think that's quite true," Chamberlin said. "We have looked for technological change on a continuous basis, predivestiture and post. It has always been an ongoing process."

To reduce the need for layoffs, C&P offers workers inducements to retire. These "buyouts" of older employes, it is hoped, will greatly reduce the dislocation, union and company officials said.

At C&P, Chamberlin said, employes 55 or older with at least 20 years' service are offered up to $400 per month in a pension supplement for four years if they retire early, or they may opt for a lump sum of up to $22,000. Younger workers who are not yet eligible for pensions are paid an incentive, on a sliding scale, if they leave C&P, he said. A nine-year employe, for instance, is paid nine weeks' salary, and a 19-year employe gets 38 weeks' pay.

After retirements are totaled, Chamberlin said, the company will determine how many layoffs are required and will meet with the union to negotiate the procedure.

In addition to the departing unionized workers, hundreds of C&P's managerial employes have already requested early retirement.