The identifications of AT&T Vice President Rex Reed and CWA President Glenn Watts were transposed in a caption yesterday.

Three unions representing about 675,000 workers on strike against the American Telephone & Telegraph Co. yesterday reached tentative approval of contracts exceeding $3 billion in pay raises, benefits and job security provisions.

Union leaders said they hoped their workers would be back on the job by early Thursday, ending a walkout that began Aug. 7.

Among the striking workers are 11,500 union employes of the Chesapeake & Potomac Telephone Co. in the District, Maryland and Virginia.

Glenn E. Watts, president of the Communications Workers of America, which represents 525,000 of the strikers, said the work stoppage would continue until all 34 of its bargaining units have approved the contract. Watts said he hoped that would occur by Wednesday night.

The CWA's 17-member executive board, meeting here yesterday, unanimously voted to approve the proposed contract.

The other unions, the 50,000-member International Brotherhood of Electrical Workers and the Telecommunications International Un- ion, which represents about 100,000 workers, also said they hoped their bargaining units would approve the contract within the next couple of days.

Any new union contract signed will be binding on the seven regional operating companies that are to be formed next Jan. 1 as part of last year's antitrust divestiture settlement between AT&T and the Justice Department.

One union negotiator said the uncertainties posed by the court-ordered divestiture of AT&T's operating companies were a stumbling block in the contract negotiations. A union spokesman said that the divestiture "played a role" and that there was a split at the management level of AT&T over committing itself to such a contract.

Watts called the tentative settlement a victory, saying the contract is "a substantially improved response by the company to their original offers in the key areas of our bargaining demands" that led to the strike. "Let me note that our bargaining hand was strengthened vitally by the members' determination and sacrifice while walking the picket lines."

The unions were able to overcome certain "giveback" proposals the company made, such as limits on cost-of-living increases and some health care benefits.

The unions' major victory was in provisions strengthening members' job security in the face of increasing technological innovations that threatened to eliminate many jobs. For example, since 1960 the percentage of telephone operators has fallen from 30.8 percent to 13.1 percent of Bell System workers because of improved technology.

Although the walkout was scarcely apparent to many consumers and businesses who place more than 500 million phone calls daily in the United States, Watts said the strike had placed other burdens on the Bell System, which had to shift supervisors to fill picketers' slots.

AT&T spokesman Charles Dynes said earlier in the day that the company had not been affected much by the strike. He said it agreed to many of the union contract proposals because, "You've got to pay good wages to attract good people."

"It's a good contract. It's a large contract," Dynes said. "These are good for employes. They're good for the company."

Dynes said the proposed contract would have no immediate effect on telephone rates. Watts said the proposal provides an average 16.4 percent wage increase for workers and projects a 21 percent improvement in worker productivity during its three-year term.

The national contracts for the other two unions were similar to those approved by the CWA executive board, Dynes said.

"Most important to us this year was the issue of employment security," Watts said. "And in this settlement we have broken real ground in protecting our members from dislocations due to changes in technology and in structure of the industry. And beyond protecting existing jobs, we have moved ahead toward providing career development opportunities for our members in this volatile Information Age."

Under the tentative settlement, the union gains:

* A company-funded training and retraining program directed toward career development and providing new skills to workers whose jobs are phased out or downgraded.

* Termination pay and retraining, relocation and job-placement assistance for workers faced with permanent reassignments or layoffs who opt to leave AT&T.

* Elimination of a company plan to restructure health insurance fees that would have shifted a greater portion of the burden to employes.

* An extended medical coverage plan for employes with five or more years of service who leave the company under certain circumstances. These employes would receive AT&T-paid medical coverage for up to six months and could continue the coverage for an additional six months if they continued to pay the premiums.

* Pension fund increases of 3.5 percent for CWA-represented employes effective Oct. 1, 1984, and Oct. 1, 1985.

* A 4.5 percent increase in pension benefits for all CWA retirees of the Bell System effective Jan. 1, 1985.

Besides job security, pay was a central issue in the negotiations. The strike began after the unions rejected the company's offer of a 3.5 percent pay raise in the contracts' first year followed by raises tied to the cost of living in the second and third years.

Under the tentative settlement, the average hourly wage would rise from $12.33 an hour to $14.35 at contract's end. Wages for all CWA members at maximum rates, which includes 90 percent of the union members, would increase immediately by 5.5 percent.

Those getting top rates are the most skilled workers, such as equipment installers and those who work with switchboard equipment. Over the life of the proposed contract they would gain $86.69 a week, bringing their average salary to $611 a week, Watts said.

Operators and clerical workers, the remaining CWA members, would receive an average wage increase of $66.39 a week over the life of the contract, bringing their weekly wages to $459.75, Watts said.

About 100 bargaining units of the three unions must approve the contract. If any unit objects to the proposed settlement, Watts said, the union's leadership would try to find out why and then decide whether workers would return to their jobs.

If the bargaining unit of one of the other unions decides against the contract, the CWA unit could decide not to honor the other union's picket line, Watts said.

Paul Gray, a bargaining committee member and a special assistant to Watts, said there is no guarantee that all bargaining units will approve the contract. It is possible that problems in these local negotiations could hold up approval, Gray said.

"When we get 34 local tables it's almost impossible to believe all are going to walk right through with no discussion at all," Gray said. "It would be a miracle if we got through with all 34 with no hitch at all. All may settle, but there's going to be some haggling and hassling."