Cable modems and internet use the same infrastructure that transmits data for cable television. This is why you often see cable TV providers that also offer internet service. An ISP that provides DSL internet uses the same infrastructure as landline phones. The copper wire that's in place for telephone services is plentiful and allows the ISP to provide internet access anywhere you can get a landline phone. Because of the two different kinds of infrastructure, you need two kinds of cable modems to interpret the data – one for cable and one DSL.
With the news that TPG has agreed to acquire and for $2.25 billion, the private equity firm announced that it would combine the operations of both companies to form a "top ten US cable operator." That's not insignificant, but as the market continues to consolidate, it's not as impressive as it once was. (See .)