In an unprecedented two-hour radio show, President Carter yesterday fielded questions from 42 citizens and revealed that he wants "fairly shortly" to start discussions with Cuba over visitation rights, fishing rights, and a new anti-hijacking agreement.

The informal, often folksy exchange, billed by moderator Walter Walter Cronkite as an "experiment in communications between the President and the people . . ." brought forth a number of presidential comments on foreign and domestic matters.

The program at times was like listening in on an old-time party line, as the President joked occasionally reminisced a bit, talked about his family, listened quietly as he was scolded, and promised to call several people back personally.

The President also said:

He considered Uganda President Idi Amin's temporary ban last weekend on Americans leaving his country to be ". . . on the border of a crisis."

His goal in the current talks over the Panama Canal is "to phase out our military operation in the Canal Zone and to insure after the year 2000 that we keep the canal open to other countries and ourselves . . . "

He has "no intention" of raising the federal tax on gasoline by 25 cents, has "never proposed any such thing and don't know where the story originated."

He expects that his restructuring of the federal income tax, to be completed and made public by the end of September, will eliminate "a great number of the loopholes that do benefit the richa and the powerful."

He does not intend to pardon Vietnam-era military deserters and "others who committed crimes."

The questions came from 42 people in 25 states over a special telephone company toll-free network.

Officials of American Telephone & Telegraph Co. had said earlier all of the anticipated millions of callers would have an equal chance to get through, although very few would make it. But as things turned out, two of the callers who got through were from Lanham, Md., and there were several calls from Wisconsin and Georgia, while half the states got no calls through.

An early sampling indicated that between 9 million and 9.5 million attempts were made to reach the President by telephone, an AT&T spokesman said last night.

Carter said at the end that he had liked the show. "The questions that come in from people . . . are kind that you would never get in a press conference, that news people would never raise," he said. "I think it is very good for me to understand directly from the American people what they are concerned about . . ."

". . . My inclination would be to do this again in the future," he said, adding that he would wait and see "how the American people react to it."

The questions ranged from broad policy issues to statements chastising Carter for his January pardon of Vietnam-era draft evaders, and for the calls he makes from time to time urging state legislators to support the Equal Rights Amendement.

Other issues he touched included the high price of coffee, whether oil companies should be forced to give up their control of other industries, his policy on any future draft, who pays his family's living expenses, the recent congressional pay raise, and the commission he will shortly send to Vietnam.

On Cuba, Carter repeated his position that the island nation 90 miles from Florida "will have to make some substantial changes in their attitude" before full normalization of relationships can take place.

But he confirmed Secretary of State Cyrus R. Vance's Friday statement that he did not intend to place any preconditions on initial discussions.

". . . You couldn't possibly arrive at a solution to some of those questions without discussions," he said, "so we will begin discussions with Cuba if they approve the idea fairly shortly on the items described."

The items were the fact that both countries claim a 200-mile fishing limit, renewal of the anti-hijacking agreement that is "about to expire," and exchanges of visitors between both countries.

Carter repeated his earlier statement that before full normalization, "I would like to insist that they not interfere in the internal affairs of countries in this hemisphere, and that they decrease their military involvement in Africa, and that they re-enforce a commitment to human rights by releasing political prisoners in jail in Cuba for 17 years. Things of that kind."

On the Panama Canal, he told a caller from Payetteville, N.C.:

"We are now negotiating with Panama as effectively as we can . . . as far as sovereignity is concerned, I don't have any hangup about that . . . I would hope and expect that after the year 2000, that we would have . . . Panama guaranteeing that the Panama Canal would be open and of use to our own nation and to other countries."

In response to the show's first question, from Joseph Willman of Sterling Heights, Mich., about future responses in situations like the detaining of Americans in Uganda, Carter said:

"It's hard to know . . . the attitude we took was to . . . deal directly with Amin in a very forceful way to let him know we were expecting American lives to be protected."

Some callers bluntly criticized the President. "Now that you're pardoned the draft evaders and you've proposed to pardon the junkies and deserters, do you propose doing anything for the veterans such as myself that served the country with loyalty?" asked Ronald Fouse of Centerville, Ga.

"I feel hat you are violating the states rights when you call in to the different states and lobby for the ERA," said Mrs. Richard Nicholson of Fort Worta, Tex.

Carter said to her that he has not "tried to interfere or put pressure on them . . . I . . . reserve the right to express my opinion just like you have a right to express yours."

Other answers included:

Carter said vertical integration of major industries is generally "not contrary to the best interests of the American people," but he wants "insured competition for leasing rights," and is worried about "inadequate" competition at wholesale and retail levels.

He said he is also concerned about "horizontal investments," as when an oil company also owns a coal mine, resulting in "not a heavy enough emphasis" on coal production.

"I would be in favor of considering divestiture," he said, "but my first preference would be to insure competition through the antitrust law and disclosure of profits at the individual levles rather than divestiture itself."

On coffee prices: "I think that we have one opportunity as consumers . . . to drink less coffee as the price goes up," Carter said, adding he didn't want an embargo.

While he now doesn't plan to reinstitute the draft, Carter would "not exclude college students" from any future ones, and would include women if necessary for "national security."

Congressmen were justified in having their salaries raised recently to $57,500 because they have high job-related expenses.

To a question about relatives living in the White House, Carter said his family pays all of their own personal expenses. "Our food is kept separate . . . all of our clothes and so forth are paid for out of our own pocket."