FRANKFURT, Dec. 21 -- Siemens AG said its telecom networks unit and Pirelli have won a 70 million euro ($62.95 million) contract from Indonesia's PT Telkom to build a fiber optic network in Sumatra. The companies, which have agreed to develop submarine transmission equipment, said the contract would span the length and breadth of Sumatra. They said it was a first step in a project by Telkom to link the islands of Sumatra, Java and Kalimantan with a submarine and terrestrial fibre optic network.