With DirecTV promising 150 HD channels (perhaps using fuzzy math) and telcos beefing up their HD offerings, you gotta wonder if the HD arms race has entered a new phase. After all, Cablevision‘s Thurs announcement that by June 28 its iO: Interactive Optimum digital tier will include 15 HD nets from its own Rainbow unit Voom suggests things are really starting to heat up. The MSO noted that the new HD additions will bring to 40 its total number of HD nets, which it touted as "the most HD available anywhere in the nation, from any provider." It’s unclear how long that title will last as other MSOs—not to mention DBS and telco competitors—strive to shout similar messages from their own rooftops. But Cablevision apparently isn’t taking any chances, announcing that it will be able to offer more than 500 HD channels over its advanced fiber network by year’s end (even though nothing close to 500 HD nets exists yet). No specifics on how Cablevision would achieve its 500-HD capacity goal, but the company said it would rely on switched digital video and bandwidth management. There’s certainly no shortage of demand: Cablevision reported 734K HD customers as of Mar 31—an 85 percent increase in HD customers over the previous year. "I think you’ll see more cable ops add Voom late this year because DirecTV seems uninterested in adding it," said Phillip Swan, pres of TVPredictions.com. "It will give the cable operators something to crow about when DirecTV is adding dozens of HD channels while cable adds perhaps 30 to 50 percent of that amount." Of course, only time will tell whether MSOs step up to the HD plate for fear of losing HD market share to competitors. But Rainbow pres/CEO Josh Sapan on Thurs sent out his not-so-subtle pitch to cable, noting "our long held view that consumer demand for more and better HD programming offers MSOs a compelling business opportunity."