What would it mean to "turn off" the public switched telephone network" as IP becomes better established? It's a real question for the Federal Communications Commission, whose Technology Advisory Committee (TAC) is supposed to recommend ways the FCC can help prepare for the day when the PSTN is "turned off," much as earlier generations of wireless networks were simply deactivated.

Among the issues is setting a date for terminating the PSTN, much as the FCC had to set an actual date…

Despite some fits and starts over the past decade, the global fixed-line VoIP market is expected to reach $40 billion a year in revenues by 2015, with more room for growth as it continues to supplant traditional voice models.

A new report from Point Topic said VoIP has more than 120 million subscribers worldwide and saw growth of 12.6 percent in 2010.

"The growth of VoIP has been bumpy but shows signs of acceleration," said John Bosnell, senior analyst at Point Topic. "VoIP…