American Telephone & Telegraph Corp. yesterday reported that its second-quarter profit rose 1.3 percent on a 0.3 percent decline in revenue from a year ago, while Bell Atlantic Corp. said its earnings were up 14.7 percent for the quarter.

Meanwhile, RCA Corp., Rockwell International Corp. and AMR Corp., parent company of American Airlines, all reported record quarterly profits.

AT&T, based in New York, said its net income for the three months ended June 30 totaled $461 million (41 cents a share), compared with $455 million (43 cents) in the same period a year earlier, when there were fewer shares outstanding. Revenue, after access charges paid to the local telephone companies were deducted, came to $8.55 billion versus $8.58 billion.

AT&T reported that for the first six months of the year, net income jumped 19.5 percent to $815 million (72 cents) from $682 million (63 cents) a year earlier. Half-year revenue edged up 0.7 percent to $16.86 billion, after access payments were deducted, versus $16.77 billion.

"We are taking those steps we need to take to build an improving performance record over the long pull, notwithstanding the difficult challenges we face in achieving our current financial goals," said AT&T Chairman Charles L. Brown.

During the latest quarter, the company introduced new business computer products, sales of personal computers continued to grow despite a slumping market and the company won a federal government contract with a potential value of nearly $1 billion, Brown said.

Philadelphia-based Bell Atlantic Corp. reported net income of $283 million for the second quarter, up 14.7 percent from the $246.7 million reported for the same period last year.

Earnings per share for the second quarter were $2.84, an increase of 31 cents per share over the same quarter in 1984.

Bell Atlantic Chairman and Chief Executive Officer Thomas E. Bolger said the results reflect the company's success in "meeting the challenge to be the preferred provider of a full range of communications products and services."

Operating revenue for the second quarter of 1985 was $2.31 billion, compared with $2.02 billion for the corresponding 1984 period. Operating expenses for the quarter were $1.7 billion, compared with $1.49 billion for the same quarter last year.

New York-based RCA Corp. yesterday reported record sales and earnings for both the second quarter and the first half, paced by a sharp rise in its television business.

Net income rose to $115.8 million ($1.36 per share), compared with $109.9 million ($1.13) in the comparable period a year ago.

Sales for the quarter hit $2.54 billion, also a record high for the company, compared with $2.48 billion in the year-ago quarter.

For the first six months of the year, RCA's net income was $180.8 million ($1.94), compared with $160.2 million ($1.53) in the first half of the prior year. Sales for the half totaled $4.94 billion, compared with $4.85 billion in the first half of 1984.

RCA, which last month agreed to sell its Hertz Corp. car rental business to UAL Inc. for $587.5 million, said NBC attained record sales and earnings, with income jumping 43 percent from the comparable quarter in 1984.

The TV network accounted for most of the improvement, with its prime-time programming strengthening in ratings in May.

Pittsburgh-based Rockwell International Corp., builder of the B1 bomber and the space shuttle, said profits for the three months ended June 30 reached $160.2 million, a 21 percent boost over $132.9 million in the same period in 1984. Earnings per share were $1.07, up 23 percent over 87 cents a year earlier.

Third-quarter sales were nearly $3 billion, up 25 percent over $2.4 billion in the 1984 period.

Income for the nine months ended June 30 climbed 27 percent to $455.3 million ($3.06) from $357.5 million ($2.32) in 1984.

Sales were $8.2 billion, compared with $6.7 billion in the 1984 period.

AMR Corp. of Fort Worth, parent company of American Airlines, yesterday reported the highest second-quarter net earnings in the company's history.

AMR reported net of $173.9 million ($2.98 a share) in the just-completed quarter, compared with $71.4 million ($1.36) during the second quarter of 1984. Net earnings for the first six months of 1985 of $234.1 million ($4.20) also broke the company's record.