Three telecoms firms have subscribed to a new undersea cable linking Nigeria and West Africa to Europe, paving the way for a transformation in internet access in Africa's fastest-growing telecoms market.

The Nigerian arm of Etisalat, South Africa's MTN and Nigeria's Starcomms are among the first to sign up for broadband services from the cable, its operator the Main One Cable Company said on Wednesday.

The 7,000 km (4,350 mile) fiber optic cable, built in partnership with U.S. firm Tyco, runs from Portugal to Nigeria and Ghana, and also branches out to Morocco, the Canary Islands, Senegal and Ivory Coast.

Main One says the cable delivers more than ten times the broadband capacity of the South Atlantic Terminal (SAT-3), Nigeria's sole existing undersea cable, and will enable service providers to offer cheaper and more reliable internet access.

Those pre-construction customers ... that have taken up our services to date are Etisalat, MTN and Starcomms, Main One chief executive Funke Opeke told investors and telecoms executives at a launch ceremony in the commercial hub Lagos.

Participants from Bangalore, London and Johannesburg took part in the launch using teleconferencing facilities -- not previously possible in Nigeria -- hosted by U.S. router maker Cisco Systems Inc, which is partnering with Main One to develop applications for the Nigerian market.

Steven Evans, chief executive of Etisalat's Nigerian arm, told Reuters his firm was testing the cable and would go live on it within a day or two.

We are working very hard at the moment to go live on the network, hopefully within the next 24-48 hours ... so that we will be one of the first people to be having broadband on the main network in Nigeria, Evans said.

Evans said the cable would enable mobile phone operators to launch enhanced services, increase speed and lower prices, boosting competition in Africa's most populous nation of 140 million people.

MTN is Nigeria's biggest mobile operator but faces tough competition from local firm Globacom and from India's Bharti, which last month completed a $9 billion acquisition of the African operations of Kuwait's Zain.

Main One's cable will close the technology gap between Nigeria and other parts of the world. The cable, which has a capacity of 1.92 terabits, can accommodate 1 million MP3 downloads and 100 million voice calls per second.

South Africa's capacity is 1.28 terabits.

(Editing by Nick Tattersall and Louise Heavens)

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