NTT Communications has signed a construction and maintenance agreement with the consortium building the Trans-Pacific Express Cable Network.

The new optical fibre cable system will link Japan, mainland China, South Korea, Taiwan and the US.

The network is being built by a consortium that now comprises NTT, AT&T, China Netcom, China Telecom, China Unicom, Chungwha Telecom, KT and Verizon Business.

Six original consortium participants began constructing the southern route at the end of 2006, which directly links the US and Asia, including mainland China, South Korea and Taiwan. This section is expected to be operational by August 2008.

The second phase will see the construction of the northern route, transiting Japan. The Japan-Asia section is expected to come online during the first quarter of 2009, followed by the Japan-US section, which should be complete in early 2010.

In its entirety, the cable network will be more than 18,000km long and have a maximum transmission capacity of 5.12Tbps.

A similar, faster submarine cable network is being constructed by a consortium consisting of Singapore Telecommunications Ltd, Bharti Airtel, Global Transit, Google, KDDI Corporation and Pacnet.

The 7.68Tbps Unity network will link Chikura in Japan directly to Los Angeles and is expected to be ready for service in the first quarter of 2010 at a cost of around $300m.