"The hotline between the leaders will be connected tomorrow and working-level officials will conduct a trial call," presidential spokesman Kim Eui-keyom said Thursday.
The two Koreas have agreed that President Moon Jae-in and North Korea leader Kim Jong-un will hold telephone talks before the summit.
He added the date of the first telephone talks has not been fixed.
The two sides will hold separate rehearsals ahead of the landmark summit, he said.
The South plans to rehearse on Tuesday and Thursday at the summit's venue, the House of Peace on the southern side of the border village of Panmunjeom, while the North is expected to use the venue for its own rehearsal on Tuesday or Wednesday, Kim said.
All subcommittee chiefs of the South's summit preparatory committee will attend the first rehearsal on Tuesday afternoon, while the second rehearsal, which will take place on the eve of the summit, will involve more people and be more detailed, the spokesman said.
The South plans to open a situation room on the third floor of the House of Peace, Kim said.
The presidential office also plans to open a situation room on the third floor of the House of Freedom near the summit's venue, Kim said. A similar situation room will also be set up Tuesday at the KINTEX exhibition and convention center in Goyang, north of Seoul, where the main press center will be located.
The presidential office said six senior officials will accompany Moon to the summit. They are Im Jong-seok, chief of staff; Chung Eui-yong, head of the National Security Office; Suh Hoon, chief of the National Intelligence Service; Unification Minister Cho Myoung-gyon; Defense Minister Song Young-moo; and Foreign Minister Kang Kyung-wha. By the Yonhap.
