CommScope Inc. agreed to be taken private in a $3.9 B acquisition by the leveraged-buyout firm Carlyle Group, the biggest takeover in the telecommunications-equipment industry in at least two years. CommScope (which had acquired Andrew Corp.), based in Hickory, NC, is working to revive sales after the global recession hurt demand last year. Carlyle is banking on an increase in demand for fiber-optic networks as phone- and Internet-service providers update their systems to accommodate increasing amounts of video and data.