There are no signs pointing the way from this small Caribbean port to the new U.S. military base, but a visitor can steer by the warlike sounds that emanate from the tropical hills to find the Regional Center for Military Training.

A Huey helicopter beats the muggy air, flitting above the trees along a hill line. Then there is the sharp staccato of M16s firing somewhere in the bush behind a fresh clearing. A turn left off the paved road in that direction and one is upon the camp set up in June for the U.S. training of Salvadoran and Honduran troops.

For an outsider who remembers other Green Beret installations on another tropical continent in another decade, to arrive at this new U.S. training camp is to be struck by an unmistakable sense of deja vu. If it were not for the Spanish that floats from the tents, this could be Vietnam.

Here, again, are the regulation fields of fire cleared from the camp periphery, the sand-bagged foxholes, the double rolls of shiny--and razor sharp--concertina wire around the operations headquarters and supply depots. Here too there is an air that stifles the lungs with humidity and heat and a raw ground of red dust quick to turn to viscous mud in the periodic downpours of the rainy season.

There is also the familiar sight of tall, gangly U.S. Special Forces troops ambling about in floppy jungle hats as they train their smaller, foreign ally recruits in the American way of making war. And although it is U.S. policy to underline the differences between the Vietnam of the recent past and Central America of today, even veteran Green Berets who have experienced both find the physical similiarities inescapable.

"We even have screaming monkeys in the tree line to wake us up every morning just like we had in 'Nam," said a Special Forces major as he conducted a visitor through the camp toward a firing range where a squad of young recruits--some no older that 15, according to Green Berets who train them--were firing rapidly at stationary targets.

"Yeah, we could just as well be back in the Central Highlands from the look of this country," said Lt. Col. John Mirus, who served two tours of duty in and around Dakto in the 1960s and still has his memories and a Silver Star to show for it. Mirus is the comander of the 125-member unit of the Green Beret group that came here in June from Fort Bragg, N.C., to open the camp. It is under the titular command of a Honduran colonel who leads two companies that provide security for the camp.

A wiry, gaunt-faced, 41-year-old officer who grew up in Pasco, Wash., and began his 18-year military career as an enlisted man, Mirus is quick to emphasize that although the place may look like Vietnam the function of his men is very different than it was in Southeast Asia.

"Our mission is limited to what is our bread and butter in peacetime: training foreign troops," Mirus says. "There is no question of our advising troops in the field. We are here to train and nothing else."

"We are only allowed to have our .45-caliber pistols here for personal defense," he said. "I think if there were hostilities the best thing we could do is to keep training more local soldiers so they could deal with it better themselves."

Mirus and his Green Berets are now in the final stages of completing a six-week infantry training course for a new Salvadoran battalion of 1,040 men that was hastily formed in February from a combination of raw recruits, field-tested noncommissioned officers and officers from previously U.S.-trained units in El Salvador.

Col. Inocente Orlando Montano, the commander of this new Arce Battalion, used to be the executive officer of the Belloso Battalion that was trained last year by Mirus' men in Fort Bragg before it was determined that it would be more economical and politically acceptable to train future Central American units in Central America.

This base is the result of that decision and the Arce Battalion is its first fruit. Unlike the Belloso Battalion, however, the Arce is not receiving the 18 weeks of training that is standard for U.S. recruits. The Arce's training was shortened to six weeks because when it was sent here the Salvadoran government was scheduled to hold national elections this fall and wanted its newest battalion back in El Salvador in time to help secure the countryside before the vote.

The election has since been postponed until sometime next year. But the Arce's training schedule already was set and it is still to return home next week, when its shortened course is over, to allow new units to come here.

The battalion's graduation is expected to be presided over by U.S. Secretary of Defense Caspar W. Weinberger who will helicopter to the camp this week during his swing through Central America.

Mirus was upbeat about the martial aptitude his charges would leave with.

"I think when these men go home they will be able to perform company-sized operations to U.S. standards," he said. "I am pretty confident they will do pretty well in the field."

That was not the unanimous assessment of his men.

"Some of these guys are real turkeys," a mortar instructor told a reporter privately at a bar in nearby Trujillo. "They got guys here who are 15 and 16 years old and many of them can't even read."

Mirus said that once the Arce Battalion returns home, a smaller Salvadoran cazador (hunter) battalion of 350 men would arrive for training and that they would be trained alongside a Honduran infantry battalion.