and Asia offers high-speed transit services from Europe to Asia via the Russian territory. international digital transit telephone network of Rostelecom is based on ten international transit and communication centers and six combined communication centers. The total installed capacity of the zonal network by the end of 2011 constituted 1,100,600 channels. The level of international communication centers digitalization constituted 100%. In May 2006, Rostelecom launched a new fiber-optic data transmission line linking Russia's Far Eastern cities of Belogorsk and Blagoveshchensk with the Chinese city of Heihe on the Chinese-Russian border. In May 2006 TransTeleCom Company and North Korea's Ministry of Communications have signed an agreement for the construction and joint operation of a fiber-optic transmission line (FOTL) in the section of the Khasan–Tumangang railway checkpoint. This is the first direct land link between Russia and North Korea. TTC's partner in the design, construction, and connection of the communication line from the Korean side to the junction was Korea Communication Company of North Korea's Ministry of Communications. The technology transfer was built around STM-1 level digital equipment with the possibility of further increasing bandwidth. The construction was completed in 2007. In 2011, Rostelecom came to an agreement with Mongolian operator Mobicom aimed at establishing a Russia-Mongolia border-crossing transmission line and at providing telecommunications services. It also opened a new international Kaliningrad-Poland transmission line through the Poland–Russia border to optimize costs when providing services to end users and operators in Kaliningrad. In February 2012, the national operator Rostelecom has selected TeliaSonera International Carrier to operate and manage its new backbone network between Kingisepp, Russia and Stockholm. The next-generation managed optical network provides connectivity between the cable landing points of the Baltic Cable System, Kingisepp and Kotka, implemented over TeliaSonera International Carrier's wholly owned fibre-optic infrastructure to Stockholm. In September 2013, EPEG International Cable System, of which Russia is a member, became in commercial use. Main line connects Western Europe and the Middle East through Russia. The line, connecting Frankfurt across Eastern Europe, Russia, Azerbaijan, Iran and the Persian Gulf to the capital of the Oman, Muscat, has an initial capacity of 540 gigabits per second. The total length of the new cable system amounted to about 10,000 kilometers, and design capacity is up to 3.2 terabits per second. Vodafone organized a main line connecting Europe with Ukraine to the border with Russia. From the Russian-Ukrainian border to the border with Azerbaijan and