The Vietnam War, which infiltrated American households by seizing control of television in a way no other war had before, will try to capture the medium again this fall.

This assault, which begins Sept. 24, comes in the form of the first dramatic series centered on the war to be developed for network television. The war that was so much a part of newscasts of the '60s and '70s, will now be the center of a weekly hour on Thursday nights.

The series, "Tour of Duty," launched by CBS, will attack the prime-time schedule at its strongest point -- the 8 p.m. slot occupied on NBC by "The Cosby Show," arguably the strongest show ever to dominate a prime-time slot.

Point man for the show is Terence Knox, who plays Sgt. Zeke Anderson, first among equals in an ensemble cast.

And a suitable choice he is to head the cast of a show that almost certainly will sustain criticism. When it comes to word games, he is no one's noncombatant.

At a press conference in Los Angeles, a reporter challenged the presence of the Vietnam Veterans of America at a CBS press conference to discuss the show.

Knox's response to the suggestion of impropriety was immediate: "Yo' momma!" he said.

Terence Knox is a happy man. After being killed off in one television series ("St. Elsewhere") and having another series killed off "I'm in a real good spot right now," he said.

For several months that spot will be the non-tourist areas of Hawaii, where "Tour" is filmed. Amid the paradise of the islands, the "Tour" crew will work seven-day weeks turning out the series of one-hour shows.

"There are different stories to be told about Vietnam," he said, "depending on when you were there and where you were. Ours is a jungle setting in '67. There is still a lot of cameraderie and good faith. The troops still get along."

The two-hour pilot is an impressive piece of work, especially given the fact that it was filmed in just three weeks. The production expense is clearly on the screen, with a lot of explosions and swarms of helicopters filling the footage.

It won't be that way every week. "There will be helicopters and we have access to Army film footage," said Knox. "But you'll get to know the characters and there'll be fewer explosions -- they take a lot of time to set up." And besides, special effects are expensive.

But the continuing element of the show will be a cast of characters the audience will have a full season to get acquainted with -- if a sniper doesn't get them first -- and a certain underlying tension and uncertainty.

And there will no doubt be sniping from the viewing audience. The pilot episode played well in screenings before the Vietnam Veterans of America this summer, but the sensitivity of the show's subject matter, coupled with its early-evening timeslot, have raised other questions about the series: Will it be too violent for young viewers watching at 8? If the show is toned down for airing at 8, will it then project a sanitized view of warfare? And is the Defense Department exercising any control over the production?

At a press conference in Los Angeles, Zev Braun, the show's executive producer, acknowledged that he was shocked when CBS chose to air the show at 8 p.m. -- early in the evening for a show that might logically play at 10 with more adult fare; and, of course, it's opposite the awesome "Cosby Show."

"I thought it was a joke" when they said 8 p.m., said Braun. But nobody laughed, and ultimately Braun accepted the CBS logic that all the 10 p.m. slots were committed to other shows and that the grim tension of "Tour" would contrast nicely with the lighter "Cosby."

And, he said, the early timeslot, normally a place for young viewers' fare, isn't necessarily a curse. "There are young people who don't know about Vietnam. I take it as a challenge. I think it's important for young people to know that war's not like Rambo."

Braun acknowledged that the Department of Defense had been very helpful -- where else do you get all the uniforms, guns, and helicopters plus advice on how to use them? -- but said he didn't feel he had traded control of the show for munitions.

But the Defense Department did get a bit touchy, he said, when it came to depicting drug use and racism among the GIs.

"They didn't want grunts to be portrayed as dopers," said Braun. "I'm not sure it's important to actually see someone smoking a joint {on-screen}. But it is important to see racial conflict. It's important to know that drugs were an important part of the war. If we can't show racial conflict, we can't show racial healing."

In the opening episode, Knox's character, selecting platoon replacements, warns that he doesn't want any druggies to follow him into the jungle.

And Braun promises that racial conflict between black and white GIs will be dealt with in later installments.

But the overriding theme of the show will be the constant threat to life and the struggle to survive. "Not every episode will have the bombastic effects of the pilot," said Braun. "But there'll always be the ever-present threat of death -- even in a quiet moment there can be a sniper. It's both realistic and dramatic."

At 36, Terence Knox appears more outgoing and irreverent than philosophical and introspective. But he seems genuinely caught up in both the work and the meaning of "Tour of Duty." A member of the Vietnam Veterans organization mentioned how Knox and other cast members signed "Tour of Duty" posters for two hours after one screening for the organization. And Knox spoke warmly of the VVA members he's met this summer.

On a promotional trip to Washington, he visited the Vietnam War Memorial. He looked up the name of an acquaintance -- "Actually, I didn't even like him much" -- and was touched when he found it.

"I was prepared to be impressed by the memorial," said Knox. "I was not prepared to be moved."