- Telecommunication Technical Service Joint Stock Company (TST), Formerly known as Kasati Hanoi Center, is a unit attached to State Enterprise, Enterprise of manufacturing information equipment, was established in 1990. In 2000, The Company transformed its business model into a Joint Stock Company. Current charter capital of the Company is VND48 billion. The Company's main business activities are: Researching, manufacturing and assembling post, telecommunication, electricity, electronics and informatics equipments. Technical consultancy, making investment projects, designing and evaluating construction projects. Importing and exporting equipment, materials, spare parts, components ... TST has a wide market throughout the country. TST's customers are provincial / city post offices, from the North to the South such as: An Giang. Bac Can, Bac Giang, Da Nang, Hanoi, Quang Binh, Quang Ngai, Long An ... A number of TST projects involved in construction and installation such as: Installation of optical cables in Hanoi, Quang Ninh, Hoa Binh , Thanh Hóa, Son La ... Installing optical equipment 622 MB / s, auxiliary power source for VTN. Installing equipment 2.5 GB / s, 5GBps, 10Gbps, auxiliary power for VTN. Installing the ERICSSON AX Switchboard ...TST has been traded on Hanoi Stock Exchange (HNX) since December 13, 2007.