Pascual Chavez stood at a narrow counter last Tuesday morning, in front of a buzzer marked "Cuban Matters," and peered intently at the visa application he had just filled out.

After looking it over with extreme care, he rang the buzzer, then waited. Ten minutes passed. Finally, the wooden window swung open and he handed the man his application and a $5 bill. The window swung closed.

Chavez, 68, first left his native Cuba in 1938. A sturdily built man, he speaks proudly of his accomplishments; he became an American citizen in 1943 and fought in Europe in World War II.

After the war, he settled in New York and lived there for 24 years. In 1969 he retired, "I ran my own little business," is all he will say of his work, and moved to Puerto Rico.

It is from there that he has come to apply for his visa. He has not been in Cuba since 1958 and his only communication with his family in Havana has been by letter.

"I want to see my brothers again," Chavez explained. "They are getting old and I do not know how much longer they will live."

Chavez may not receive his visa. His brothers are getting older but none is older than he and none is ill. Like many other, Chavez may be turned down after a wait that can be as short as three weeks, as long as three months.

"The only Cubans who we are granting visas are those who need them for humanitarian reasons," said Clemente Sorciano, second secretary and consul of the eight-man Cuban Interest Section that arrived in Washington Sept. 1. "I would say 90 to 95 per cent of the Cubans requesting visas are turned down."

Humanitarian reasons, according to Soreiano, consist of having very ill or aged relatives. In that case a Cuban who voluntarily left the country can return for a visit - otherwise, no. It does not matter when the person requesting the visa left Cuba.

Thus, seven months after President Carter lifted the ban on American travel to Cuba, a sad irony has emerged: Virtually any American who wishes to visit Cuba can do so. Any Cuban who wants to visit, probably cannot.

Most of those who come to Washington looking for visas are Cubans. Many come, according to Soreiano, even after being told they will probably be turned down.

The Americans who apply for visas are more reluctant to talk than the Cubans. They give business reasons that range from plastics to theater interest on their applications.

"Please don't use my name," one said. "If I'm in the paper or they think I'm discussing anything I might get turned down." The man added that he had traveled to Cuba during the ban - as many Americans did - but preferred to travel with an American passport if he could.

Acquiring a vista for business purposes, if you are an American, is not difficult. Tourists can visit Cuba through travel agencies that set up charter groups. No commercial American airline has resumed scheduled flights.

The Cuban Interest Section, whose members will work out of the Cuban Embassy, is still a long way from being operative. Thus, for the moment, the Czechoslovakian Embassy continues to handle visa requests as it has since the travel restrictions were offically lifted on March 18.

Soreiano said he hopes the Cubans will take full control of the operation by the end of October. Right now the embassy is virtually bare. The main hall is empty except for the thick red carpet and a lone coat hanger.

"We will have much work to do here," said Soreiano making a sweeping gesture with his hands. "We are not yet ready."

While the Cubans prepare, the Czechs keep the Cuban section in their Embassy open from 9 a.m. until noon daily. The interest section consists of a small room, perhaps 15 feet by 30 feet large.

In the room is a sample copy of the visa form filled out in Spanish and people such as Chavez stand at narrow counters to fill out the forms - when there is space.

There are two buzzers, one marked "Cuban Matters, the other "Czechoslovakian Matters." The second buzzer is rarely used.

When someone rings the buzzer it often takes 10 minutes before the window is pulled open. A question will result in the window being shut and another wait of 10 minutes. One man used a $10 bill to pay his $5 application fee and had to wait 10 minutes for his change.

Many of the Cubans or middle-aged or elderly and speak English with noticeable accents, say they want to return to visit family. 'My mother is 91 years old," said Dora Gonzalez, who drove from New York with her husband Joseph. "If I do not return soon I will not see her," Gonzalez first came to the U.S. in 1946.

Soreiano said it normally takes from three to four weeks to process and approve a visa application. Some of those applying said they have been told by friends it had taken them two or three months. Soreiano did not deny this possibility.

"It is extremely difficult when you have to deal with a third party," he said. "They (the Czechs) must check with Havana on everything. We expect things to be easier when we are in charge."

Soreiano said there had been more than 10,000 inquiries the first week the ban was lifted but had no idea what the total number of application was to date.

It does not appear likely that the confusion and difficulty connected with acquiring the visa will disappear for Cuban natives anytime in the near future. Soreiano said the government was considering the possibility of allowing those who wanted to return to live in Cuba to do so. 'Some of them, not all," he added.

Many of the Cubans cannot understand why they are being prevented from returning home. "I came here in 1971," said Antolin Brito, a small slightly built man, who shivered slightly as he waited his turn in the cold room. "I went to Miami because my daughter (who lives there with her husband and family) was very ill.

"My wife, my son and my six brothers are still in Cuba. I have not seem them for six years. I do not know if I can go back now. They do not tell me."

And Victoria Gonzales, who moved to Miami "to look for work," in 1957 also wants to see her family. She has not been home since 1960.

"I don't want to cause them any trouble," she said. "I will wait and go when they tell me."