 Bloomberg -- Britains biggest landline network has brought on a new supplier to help cut its reliance on Chinas Huawei Technologies Co. and ramp up construction of a nationwide fiber-optic system.BT Group Plcs infrastructure unit Openreach signed a long-term contract to bring in U.S. firm Adtran Inc. alongside Huawei and Finlands Nokia Oyj as a strategic partner. Adding an American component maker will help London-based BT limit the use of Chinas Huawei technology in its fiber-optic network and meet national security rules. The parties didnt disclose financial terms.In January, Britain capped the amount of data that can be carried over Huaweis full-fiber and 5G equipment at 35, and gave networks three years to comply. The move dealt to a blow to the Shenzhen-based vendor, but stopped short of U.S. demands for an outright ban.Huawei makes up 44 of the U.K.s full-fiber market, according to the government. BT said overhauling systems to obey the rules may cost it 500 million pounds 611 million, though mainly it pointed to the changes it needs to make to wireless towers.It helps Openreach to be able to execute on their plan and still abide by those requirements, Jay Wilson, Adtrans chief revenue officer, said in an interview. The contract could make up a 10th of Adtran sales during the peak of its build, he added. The Huntsville, Alabama-based company also supplies some of BTs small startup rivals, as well as big U.S. carriers like ATT; Inc. and European peers like Deutsche Telekom AG.Read more: Britains Plan to Get Working Again Doesnt Seem to Be WorkingThe contract comes a week after BT accelerated its planned fiber rollout, pledging to connect 20 million premises by the mid- to late-2020s if conditions allow. It also scrapped dividend payments to help pay for the pledge, and rivals Telefonica SA and Liberty Global Plc announced the same morning that they were merging their U.K. units to create a stronger rival to the former state monopoly.Bloomberg first reported Openreachs search for a new supplier in November. Peter Bell, the companys network technologies director, said in a statement that the Adtran deal would help the U.K. bounce back from the Covid-19 pandemic with a better broadband network. The U.K. has lagged behind European neighbors in building out glass-based fiber connections, relying instead on lower-bandwidth, copper-transmitted wires.For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.2020 Bloomberg L.P. 