The loud 'bang' heard yesterday was the sound of the wireless walled garden crumbling under the blow of open access.

Verizon Wireless' decision to open its wireless network to outside handsets, applications and other devices is a sure sign that the business model for U.S. mobile operators is changing, and changing rapidly. Prior to this announcement, Verizon Wireless was considered the most closed of wireless carriers, restricting where its wireless data customers could travel electronically and carefully certifying applications and handsets used on its CDMA network.

That the company is seeing the need to open its network for those customers who want faster innovation than a tightly controlled network can allow should make it clear to other wireless network operators where the future lies. That future actually became apparent in the U.S. earlier this summer, when the launch of Apple's iPhone touched off online competition to hack the system to avoid using AT&T as a service provider. That feat was accomplished -- and celebrated online -- rather quickly. The attempt to force anyone who wanted the innovative iPhone to use only one service provider didn't sit well with many consumers.

Wireless service providers in other markets -- Europe and Asia, for instance -- have been more open than U.S. carriers for years now, allowing customers to attach any GSM-compatible device to the network and to take their phones with them when they changed carriers. In this regard, the U.S. is just now catching up. That has been the traditional order of things in the wireless world, however -- innovation has first occurred outside the U.S., then later been adopted here.

Verizon's decision creates new challenges for the wireless operator, not the least of which is living up to the promise of enabling its CDMA network to be truly open.

But this move, in fact, was almost inevitable. U.S. regulators are leaning toward a more open access approach for new spectrum, such as the 700 MHz chunk being opened for auction beginning in January, and when -- maybe if -- WiMAX takes off in 2008, it could also introduce a more open approach to wireless data.

And, as wireless services become more advanced regarding what consumers can do and view, and not just about who they can talk to, open is the only logical approach. Consumers today would not stand for being forced to buy their PC, MP3 player and digital camera from the same company that provides their Internet access. They will increasingly resist the notion that wireless services require the same kind of bundling.

GSM network operators are ahead of the game on this because of the interoperability of handsets and SIM cards on the network. Real openness will go farther, however, to allow content, applications and, yes, advertising from other service providers to be accessible from a wireless-enabled device.

Verizon says it is taking that first step to being open -- the company still must back up its big words with action, but it is at least moving in the right direction.

E-mail me at cwilson3@telephonyonline.com.