The final lines in a unique chapter in the history of international television broadcasting are being written in Korea.

For 50 years, the Armed Forces Network in South Korea entertained the tens of thousands of troops based here, broadcasting from just south of the world’s most heavily fortified border.

In addition to serving the U.S. Armed Forces stationed in Korea, AFKN, as it is known, has been an integral part of broadcasting here, bringing American content and culture to local viewers, including many opinion makers in the modern Korean entertainment industry.

But now, because of rising concern among U.S. television networks about intellectual property rights protection as well as changes in the structure of the U.S. Forces Korea, the network is going off the air for millions of cable TV subscribers.

American networks provide their programming to AFN to broadcast in Korea and around the world at greatly reduced rates or free of charge on the condition that members of the U.S. military and its civilian contractors are the only viewers.

But in South Korea — which hosts 30,000 American troops, including those living in a 630-acre Yongsan Garrison in the heart of Seoul — many cable service operators retransmit that signal without permission.

With South Korea’s homegrown television all the rage in Asia and a surging domestic appetite for foreign programming, U.S. networks increasingly view the unauthorized retransmission of AFN as a danger to the value of their content. The networks threatened to pull out of AFN if the illegal retransmission continued.

“We gently brought this up with the Korean Broadcasting Commission, telling them this situation could affect our programming worldwide,” said Col. Franklin Childress, USFK public affairs officer. “They said, ‘You’re right,’ and agreed with the cable companies to take AFN off the air.”

Some already have removed AFN; AFN Korea should be done by February, with complete compliance around the world taking until May.

When AFN does go dark in most Korean households, it will mark the end of an era.

AFN made its Korea debut on Sept. 15, 1957, just three years after television was added to the Armed Forces’ broadcasting system and four years after the end of the Korean War.

Television was just a year old in Korea then, started by an RCA salesman to spur demand for TV sets. The only local channel, HLKZ, broadcast just two hours a day, compared with five or six by AFKN.

When the HLKZ building was gutted by fire in 1959, AFKN allowed the Korean channel to use its facilities for more than a year. When Gen. Park Chung Hee led a coup to oust then-president Syngman Rhee, engineer John Soon-jae Lee made the announcement on the air. “It was the first time Korean was spoken on AFKN,” said Lee, an AFKN engineer from 1958-64.

On New Year’s Eve 1961, South Korea finally got a full-fledged channel, today’s Korean Broadcasting System. Ties between AFKN and local broadcasters were naturally strong in those days. “I trained all the first engineers at the Korean channel back then,” Lee said. “Gen. Park just wanted television for propaganda.”

For many, AFKN provided a first look into American culture. Filmmakers such as Bong Joon-ho, director of last year’s hit monster movie “The Host,” watched movies on AFKN, intrigued by the obvious censorship of violent films.

“I used to notice the cuts and imagine what was missing,” Bong said.

For others, the Saturday morning cartoons were the hot draw, especially when they broadcast Japanese anime that was then banned in Korea.

“I did not understand it because it was in English, but I still liked to watch,” said Choi Jae-won, head of the film division at Barunson and a major Korean film producer. “A lot of people were like that.”

Although some Seoul residents will continue to get AFN via antenna for now, even that option will come to an end. Once the Seoul USFK base relocates 90 kilometers south, AFN will go satellite-only in Korea.

“The Yongsan transmitter is aging, and we don’t know how long it will last,” Childress said. “Once we relocate in 2012 to Pyeontaek, there will be no transmitter there.”