UPDATE 1-Telecoms operators sign African undersea cable deal

* Cable to be ready by 2011

* Project to cost $600 mln

* Alcatel-Lucent contracted to supply cable

(Adds details)

JOHANNESBURG, April 8 (Reuters) - A consortium of telecoms operators have signed a deal that would pave the way for the laying of South Africa's undersea cable around West Africa to Europe, local telecoms firm Telkom TKGJ.J said on Wednesday.

The $600 million West Africa Cable System would boost broadband capacity and could cut comparatively high Internet tariffs in Africa’s biggest economy.

The 14,000 km long cable system, which is expected to move data at 3.8 terabits a second, would be supplied by Alcatel-Lucent Submarine Networks and was expected to be completed by 2011, Telkom said in a statement.

Telecommunications companies that have signed the WACS Construction and Maintenance Agreement include Angola Telecom, Broadband Infraco, Cable & Wireless, MTN Group MTNJ.J, Portugal Telecom PTC.LS, Sotelco, Tata Communications TATA.BO, Telecom Namibia, Telkom SA, Togo Telecom and Vodacom.

SEACOM, a Mauritius-registered private equity venture, has said it plans to launch a 15,000 km undersea cable that links east Africa to Europe and Asia in June this year. (Reporting by Tiisetso Motsoeneng; Editing by Andrew Macdonald)