In 1989/1990 Siemens was involved in two other significant projects designed to upgrade the Iranian telecommunications network: one for the conversion from analog to digital switching and communications technology, and the other for expansion and modernization of local Iranian production activities in the telecommunications sector. The majority of switching center equipment was manufactured in Shiraz by ITMC. In the same year Iranian Telecommunications Industries (ITI) and Siemens signed a 15-year know-how transfer contract for the production of digital transmission equipment, including the 140 Mbit/s PCM 30 Multiplexer 2 and optical fiber communications equipment with up to 140 Mbit/s, primarily designated for regional networks.
In 1993 TCI signed a DM 6 million contract with Siemens for purchase and installation of software necessary to make changes in TCI's digital systems and also to help with design of new systems.
Currently Siemens and ITMC have contracted for more than 2 million ports in 125 projects including an international gateway exchange. At the same time, ITI Shiraz implemented several important projects involving digital communications technology with Siemens and TCI.
A pilot project for conversion from the plesichronous digital hierarchy (PDH) to the synchronous digital hierarchy (SDH) featuring the bit rates 155 (STM1) = 622 (STM4) = 2,500 (STM16) Mbit/s are currently underway at TCI. In order to support the practical application of this new technology both in planning and implementation, ITI, TCI and Siemens are currently developing a joint training program. Other major contracts were awarded to Siemens in the communications cable sector.