ZTT Brand Guidelines: The Rudong Optical-Cable Maker That Went to Sea

An optical-cable maker on the coast.

ZTT is the brand of Jiangsu Zhongtian Technology, a cable and energy-equipment group from Rudong county in the city of Nantong, in Jiangsu province on China’s east coast. A Nantong city government page dated August 2026 describes the group as based in Rudong, and its optical cable work as rooted in the town of Hekou there.

The company tells its own history in stages. It says it began in optical-fibre communications in 1992, moved into the smart grid in 2002 and into new energy in 2011, and that by 2020 its products were exported to 160 countries and regions. Its website also carries the line “Since 1978” beside the group name. Its timeline lists the first steps: in 1992 it began developing and making communication optical cable; in 1994 its cable won a gold award at a Chinese high-technology fair; in 1995 it developed its first underwater optical cable for the waters of the Yangtze; in 1996 it gained ISO quality certification.

Listing followed a decade later. ZTT says the company’s shares were floated on the Shanghai Stock Exchange in 2002, and in 2022 it marked thirty years of the group and twenty years as a listed company. Its timeline names Xue Jiping as chairman across those years.

One well-documented product of those early years is a cable for power lines. The Nantong government page says ZTT’s all-dielectric self-supporting optical cable, a fibre cable strong enough to hang between pylons without a metal messenger, was developed, refined and mass-produced in Hekou, and that China’s Ministry of Industry and Information Technology recognises it as a national manufacturing champion product. The company says it received that title in 2017.

From river crossings to offshore wind.

ZTT went to sea at the end of the 1990s. By its own timeline it entered marine systems in 1999 and began developing and producing submarine optical cable; in 2002 that cable passed a national appraisal and was listed as a national key new product; in 2004 it set up a dedicated submarine cable company; and in 2007 its deep-sea optical cable and joint box passed national appraisal. In 2000 it formed Zhongtian Hitachi, a cable joint venture, and developed OPGW, the optical ground wire that runs along the top of high-voltage power lines.

Power cable under the sea became the larger story. ZTT says that in 2020 it delivered the first domestically made ±400 kV flexible direct-current submarine cable. The Nantong government page reported in August 2026 that the group won the only gold award in the cable sector at the 26th China Patent Awards, for an invention patent on flexible direct-current submarine cable, along with awards for four other patents covering specialty optical fibre, high-strength conductors, all-dielectric cables and radio-frequency systems.

The work has reached Europe. offshoreWIND.biz reported on 25 August 2023 that Zhongtian Technology Submarine Cable had secured a contract with the German grid operator 50Hertz for the eastern part of the grid connection for the Gennaker offshore wind farm in the Baltic Sea: a high-voltage route of about 88 kilometres, roughly 55 offshore and 33 onshore, plus a bypass link of about 21 kilometres between the two offshore substations. Hellenic Cables won the western lot on the same day, the report said.

ZTT also builds and installs. Its marine equipment pages list cable-laying vessels, one of them with dynamic positioning and room for 6,000 tonnes of cable, along with the jack-up installation platforms ZTT 7 and ZTT 8 and the floating crane ZTT 9, used for offshore wind turbines. The same unit offers accessories such as submarine cable joints and bend restrictors, and ocean observation networks for seabed monitoring.

Design and documentation.

Optical fibre and submarine cable are hard things to picture. The working product is a strand of glass thinner than a hair, or a cable that spends its life on the seabed, so the companies that make them borrow images from the process instead. The most familiar is the fibre itself: glowing strands fanned out against a dark ground, light running along their length and spilling from the cut ends.

Factory pictures come next. Fibre makers show preform towers, the tall draw towers where a glass rod is heated and pulled into fibre, and long rows of spools. Submarine cable makers show their ships: cable ships alongside a quay, giant circular tanks of coiled cable in the hold, and ploughs or remotely operated vehicles lowered over the stern. World maps traced with submarine routes, each line ending at a landing point on a coast, carry the same story on a website or a trade-show wall.

People appear mostly at work. Technicians splice fibre inside clean tents on a deck or a beach, engineers check repeaters on a test bench, and crews guide cable ashore at a landing site. The trade also has its own stages, such as the OFC conference for optical communications and the SubOptic conference for the submarine cable industry, where the same strands, cross-sections and route maps return on booths and slides.

This guide looks past those shared images to what can be checked about each company: who founded it, who owns it now, where it makes its fibre or cable, which systems it is known for, and which events in its history, from mergers to changes of owner, shaped the name it trades under. Where a claim rests only on a company’s own word, we say so.

Three capitals, ZTT.

Manufacturing has spread beyond Jiangsu. ZTT’s timeline records a factory in India set up in 2012, one in Brazil in 2013, plants in Indonesia and Morocco established in 2017, with the Indonesian plant opening and building starting in Morocco in 2018, the purchase of a high-voltage cable plant in Turkey in 2018, and a factory in Germany that began operating in 2019, the same year it set up a further submarine cable company. The Nantong government page still describes the group as based in Rudong.

The company now describes itself as a group of several industries: communications, power, marine, new energy and industrial internet. It lists national honours including the China Industry Award, which it says it received for the sixth time in 2020, and the National Quality Award.

The brand itself is spare. The three capitals ZTT appear across the group’s websites and in the names of its installation platforms and crane vessel, ZTT 7, ZTT 8 and ZTT 9, while the full Chinese name, Zhongtian, is the one used for the listed company in Shanghai and in the trade press reports of its contracts abroad.

For a design guide, ZTT shows how an initialism can travel from a coastal county to European grid projects. Compare Hengtong, another Jiangsu maker of fibre and submarine cable, and Prysmian, the Italian cable maker. For this guide we use an estuary blue and a copper on deep ink with a sans, an unofficial interpretation; no product or logo is reproduced.

Keep ZTT’s identity on hand — save it to a board in the Made Good inspiration library.