As the Cubans cleverly call it, Radio Bemba, meaning roughly the Network of the Lip, was broadcasting incessantly and feverishly on the island this week.

The prospect of leaving the jails and finally being free to leave Cuba, rejoining friends and family abroad, activated the word-of-mouth network that unites the huge fraternity of Cuban political prisoners, past and present.

Many thousands will be affected by the agreement worked out this week by President Fidel Castro and Cuban exile representatives. But they seem as puzzled as they are elated about when, how and whether they will leave.

There is a bittersweet air to it -- joy over Castro's new policy, but apprehension about the Carter administration's attitude toward them and how quickly their applications to enter the United States will be processed.

Castro emphasized the "moral obligation" of the U.S. to open its doors to those who want in, because Washington had encouraged and financed much of the subversive activity that led to the imprisonment of many of them.

Not surprisingly, many present and former political prisoners agree. It comes as a mild shock to hear men and women, who denied their guilt at trials now admit openly in interviews to past ties -- direct or otherwise -- to the Central Intelligence Agency.

Exiles claim that the Cuban government has held up to 80,000 prisoners since 1959. Former prisoners here, basing their guess on jail numbers assigned consecutively to detainees, think that may be close. Castro told exile delegates that about 14,000 had been freed in 20 years.

He also told them this week that 3,238 political prisoners are being held presently. Another 425 are considered war criminals -- mostly from the Batista era -- and 600 more are held for trying to leave Cuba illegally.Castro overthrew dictator Fulgencio Batista in 1959.

Castro said that about 80 percent of these 4,263 will be freed under the new policy. The remainder -- largely individuals thought to be potential terrorists -- will be considered later, Castro said.

Only the government knows how many have been held since 1959, but whatever the number, none comes close to describing the enormous human dimension of the story of Cuba's political prisoners.

It is, in a word, overwhelming: Families divided, men desperate to join wives abroad, people who refuse to yield to the realty of the new Cuba, men of all social classes made brothers by ordeal, people freed from cells but still prisoners in spirit.

Interviews with several dozen past and present political prisoners produced insights of this kind about their situation:

Many prisoners have received early releases, but must report monthly to the government. Jobs are provided for ex-prisoners, but invariably in low paying blue-collar situations, irrespective of previous training.

Torture and mistreatment of prisoners was virtually stopped 10 years ago. Today's prisoners are expected to work but they are paid -- some as much as $230 per month. They get three day passes every six weeks, with extra time off for good behavior or for doing extra work.

Cuba maintains more than a dozen political prisons around the country, but a number of others have been shut down. The largest is the Combinado del Este prison near Havana. Conditions are generally clean; visitation rights, liberal. Political indoctrination programs are not conducted.

Only in unusual cases are foreign journalists allowed inside the prisons. Yet there are no apparent official efforts to prevent contact with prisoner fraternity nor to restrict former prisoners' movements.

From these generalities come the powerful stories of the individuals, people who are doing or have done their time -- a third or a fourth of a lifetime away from families -- eager to leave to start all over.

Willie Coloma, 37, spent 14 years in prison -- one term for smuggling arms, another for sneaking art objects out of Cuba through a foreign embassy. He last saw his parents and brothers and sisters 18 years ago.

He was trained in the sugar industry, but works now as a crane operator, earning about $360 a month -- considerably more than other laborers because his job is hazadous.He says the money is barely enough to support his wife and baby.

"I do not understand why the U.S. delays -- I want to go, I have paid my debt here," Coloma said. "My family has a business in the States. We will not be a burden on the government."

Alberto Muller Quintana, 38, a former student leader who was freed last year after 15 years in jail for subversive activity, wants to rejoin his family in Florida.

Muller, a construction programmer and informal leader of ex-prisoners, said, "We are concerned that the U.S. does not give a rapid response to this human rights problem. The former prisoners cannot lead normal lives here."

Raul Alfonso, 45, a lawyer and one of nine journalists still in prison, was arrested in 1961 accused of arms trafficking and sabotage. A plan to blow up an electric power plant was foiled but Alfonso was tried and convicted in 1962.

He denied the accusation at his trial. But was he guilty? "Yeah," he said. "I did it."

Alfonso, like thousands of other prisoners, sympathized with the Castro revolution at the start but soured when the violent leftward swing began.

"I was against Batista and I sympasized with everyone who was against Batista. But I am also an anticommunist and I didn't like the new system, " he said.

Alfonso, nearing the end of a 20-year sentence, was interviewed while visiting his family on a five-day pass. He said he had served in 20 prisons, undergone no torture, and had sent considerable time doing farm work on the Isle of Pines.

He earns a salary of $230 a month, which supports the four Alfonso children who have grown up without a father in the home. "It is a long story of hard work and love, how we have stayed together," Alfonso said.

Conchita Alfonso, his wife, said, "I always tried to talk to the children as though their father was right here at home ....It has been difficult."

"That is why we are so grateful to all who have come to help," she continued. "For 19 or 20 years no one cared about what was happening in Cuba. We are talking about the same human rights as in Russia or Nicaragua or Chile -- wherever there are political prisoners."

"Anyone who does not have freedom suffers from the same thing," she said. "But now, our youth is gone."