Sixty years after telephone lines between North and South Korea were cut, communications officials from the world's most wired country and one of the least joined fibre-optic cables at the border.
The cable linking Seoul and Pyongyang will be used next month for the first video reunions of families torn apart by the 1950-53 Korean War.
South Korean businesses with operations in the North Korean town of Kaesong can also access them.
KT Corp, South Korea's top fixed-line and broadband operator, said the cable joined today will allow simultaneous connections of up to 9,600 telephone lines.
The online reunions will add to brief face-to-face meetings of nearly 10,000 Koreans over the last five years. Ten rounds of such meetings have been held.
South Korean Unification Minister Chung Dong-young proposed the long-distance reunion format when he met North Korean leader Kim Jong-il last month.
Kim accepted the proposal as an ‘exciting idea’ and suggested 15 August for the launch.
That date is Liberation Day marking the end of Japanese colonial rule over the Korean peninsula in 1945.
The two Koreas were split between the capitalist South and communist North soon after.
