mBlox is often described as a mobile transaction company, an authentication and settlement provider, even a wireless merchandizing firm. But one term that doesn’t come to mind when describing mBlox is wireless capacity wholesaler.

A data wholesaler is exactly what mBlox is aiming to become, though. Last week it announced plans with Vodafone to launch an off-deck music purchasing service that defrays the customer’s per-bit cost of downloading a multi-megabyte song by purchasing airtime directly from the wireless carrier. In English, that means instead of a customer paying $2 song and an additional $20 to download such a large file over a 2.5G or 3G network, mBlox will buy cheap capacity from the operator, which will incrementally rather an exponentially increase the overall song purchase price of the song.

This kind of arrangement has been virtually unheard of in the industry, mainly because the carriers are very protective of their data revenues, said Andrew Bud, executive chairman of mBlox. Their main fear is if they start charging 50 cents or less for a megabyte of capacity, Bud said, then the floodgates will open to VoIP and other services that will challenge their core revenue models. But Bud said that its arrangement with Vodafone stipulates that capacity can be used only for music downloads; therefore, no one could appropriate that bandwidth for something as mischievous as VoIP. While the carrier would get only a fraction of the data access revenues it normally would, it would still receive its per-song fee for a third-party transaction and it would encourage widespread take-up of over-the-air music downloads—a space that’s practically dead right now except for the few carriers that have their own music portals, Bud said.

“Data has a different value, depending on what it’s used for,” Bud said. “We need to evolve to a model where we bill for the service rather than the data itself.”

Carriers already charge drastically different rates for different kinds of data: an SMS message uses such little network capacity that SMS per-bit costs come out to be about $1000 per megabyte, Bud said. It’s easy to imagine a business model where different services have different data prices: mobile TV running at $100 a megabyte, mobile music downloads running at 50 cent a megabyte and Web browsing at $5 a megabyte, Bud said.