Cisco Systems will <A HREF="http://news.zdnet.com/2100-9584_22-5960479.html?tag=zdnn.alert">buy cable TV equipment maker</A> Scientific-Atlanta for $6.9 billion, the companies announced Friday. This acquisition marks a major strategy shift for Cisco, which has increasingly expanded its business into the home. The Scientific-Atlanta acquisition also firmly plants Cisco in the video market. With this gear, it will provide cable operators and the phone companies that also are entering the paid TV market an end-to-end solution for delivering video service.