Yesterday, Time Warner Cable started boosting the downstream speed of its most popular Internet tier from 10 Mbps to 15 Mbps in the Carolinas, Virginia, Alabama, New York, New Jersey and New England.

Like other cable operators, Time Warner Cable knows that its profit margins are in broadband, as opposed to video. During its third-quarter earnings call last month, Time Warner Cable President and COO Rob Marcus said the nation’s second-largest cable operator would increase its Standard tier downstream speed by 50 percent, to as much as 15 Mbps.

A spokesman for Time Warner Cable said this morning that the Standard tier increase was taking place across the company’s entire footprint this month.

Time Warner Cable Standard subscribers can enable the faster speed by hitting “reset” on their modems, or by unplugging them for 10 seconds and then rebooting them.

By increasing its Standard tier download speed, Time Warner Cable hopes to lure more customers over from DSL-based services.

In the third quarter, Time Warner Cable added 85,000 data subscribers, which missed analysts’ average projection of 96,000, while its broadband services revenue grew 14.3 percent.

AT&T’s U-verse data products are available in about 25 percent of Time Warner Cable’s footprint, while Verizon’s FiOS services are available in about 12 percent of the homes passed by Time Warner Cable.