Optical fiber channels are rapidly gaining an important foothold in the Iranian telecom network, partly due to cost-effective, fully domestic production of a variety of fiber optic cables and systems. In 1996, 2,010 km of fiber optic cable interconnected some major local exchange centers. The total length of the long-distance fiber optic cable network in Iran is currently 12,000 km.
At the end of the second five-year development plan, (20 March 1999), an extensive nationwide fiber optic network became operational that provides high-bandwidth connections between all provincial capitals and major cities. Transmission systems use Synchronous Digital Hierarchy (SDH) technology with a capacity of 155 Mbps for radio equipment and 2.4 Gbps for optical equipment. This enables the establishment of 30,000 voice circuits through each fiber optic cable pair.
As part of future plans for development of the optical communication network in Iran it is expected that the total length of the long-distance fiber optic cable network will increase to 15,000 km of buried cable for the main network; 14,000 km of aerial cable for the alternate routes; and 2,200 km of main cable network for the international Trans-Asia-Europe (TAE) project which provides approximately 900,000 circuits.
The Trans-Asia-Europe (TAE) ``Silk Road" fiber optic network, connecting Shanghai, PRC, with Frankfurt-am-Main, FRG, via two redundant lines through northern Iran, currently puts 33 Iranian cities directly on line with Europe and the Far East and provides high-bandwidth access for the rest of the country. The system comprises 1,550 nm mono-mode fiber optic cable using SDH transmission technology operating at the STM-4 (622.080 Mbps) data rate, with the possibility of being speeded up to STM-16 (2.488 Gbps). The system as currently configured can carry 7,560 channels of traffic. All of the cable and transmission equipment used in the Iranian and Turkmen sections of the TAE was manufactured in Iran.