LAS VEGAS--Verizon Business this week announced new mobile extensions for PBXs that allow businesses to make their mobile workers more productive while keeping corporate networks more secure.

The new PBX Mobile Extension offering is based on software from Ascendent Systems, a subsidiary of Research in Motion, that can be deployed on standard off-the-shelf servers and deployed in conjunction with a TDM or IP PBX. It replaces an earlier PBX mobile Extension offering, announced in June of 2007, that was hardware-based.

Enterprises who are customers of Verizon Business and Verizon Wireless can order the service through Verizon Business, although they will continue to get two separate bills. The service can work with any mobile phone from any wireless provider in the U.S., however, and will let mobile workers move from desk phone calls to cell phone calls and conduct conference calls from a cell phone as if they were in the office.

The service, which will be available in May, enables mobile workers to stay linked to their home PBXs for unified communications functions such as having business calls roll to corporate voice mail, transferring of calls from the mobile handset to office extensions, dialing four- or five-digit office extensions, and voice continuity in the event of outages.

For mobile workers using Blackberry 8000 series devices, there is an extra level of functionality such as the ability to support two phone numbers – one personal, one corporate – with two separate feature sets and toggle back and forth from one to the other, depending on the nature of the call.

“We know that 63% of the US workforce is considered mobile – whether traveling, working from home or working from another location,” said Stephanie Souder, product marketing manager for emerging technologies. “On top of that is the IP transformation. We as Verizon Business want to be able to deliver a single customer experience, to support any and all devices, with a single ID and single inbox.”

The higher level of integration of the Blackberry devices lets mobile workers use enterprise desk-phone features through an easy-to-use menu built into the BlackBerry phone application. For personal calls, the Blackberry user can toggle to the personal number and the call is based on the personal calling plan while for business calls, the call is billed to the corporate account.

Among other things, Souder said, mobile workers can use a single phone number that will ring up to four separate devices, and can use a Web GUI to set up the policies for how calls will be routed, and change that dynamically.

A mobile worker in the airport on a business trip “may be waiting for an important call when another call comes in,” Souder said. “She can let that call go to her corporate voice mail, and then answer the important call when it rings as if she were sitting at her desk.”

By supporting both TDM and IP PBXs, Verizon Business isn’t forcing corporations to upgrade to get the benefit of Unified Communications, nor do they have to swap out phones, Souder said.

Administrators have their own Web-based GUI interface for establishing corporate policies, classes of service and security rules.

Non-BlackBerry users can speed dial into the corporate PBX from their mobile phones and get the advantages of 4-5 digit dialing, transferring calls and initiating ad-hoc conference calls, Souder said.