Motorola, Avaya, and Proxim, today introduced an enterprise platform that enables voice roaming between enterprise WLANs and the wide area cellular networks: The solution includes a new handset from Motorola that looks like a typical cellular flip phone but can support voice over WLAN as well as voice over a GSM network. As part of the solution, enterprises must implement APs built by Proxim and Avaya, a call manager gateway from Motorola that enables the handoff between the networks, and an Avaya IP-PBX.

The phone automatically reverts to the WLAN when it's available and can seamlessly hand off calls from the WLAN to a GSM network as a user moves between them. While it looks like a cell phone, it features a lot of the capabilities of a desk phone such as buttons for mute, hold, and speakerphone. It runs Win CE so can support Microsoft .Net applications and it includes a VPN. The gateway enables push-to-talk while users are covered by the WLAN.

The platform offers some features that aren't available on the PDA introduced yesterday by HP and T-Mobile, namely voice over WLAN. "It's exciting to see the HP/T-Mobile solution, but it's an iPaq that has GSM voice on it," said Chris White, director of business development for enterprise seamless mobility with Motorola. "It doesn't do VOIP except with a softphone."

In addition, because of that WLAN voice capability, the Motorola solution supports a single phone number that rings for users regardless of the network they are connected to. Users can also use a single mailbox and access many of the same PBX-type features both inside the office over the WLAN and outside on a GSM network.

I originally thought, as reported here earlier, that one major difference between the HP handheld and the Motorola phone was GPRS but it turns out that the Motorola phone does also support GPRS. Motorola doesn't mention GPRS in its press release and didn't mention GPRS during its hour-long conference call this morning. It's surprising that Motorola would want to bury that fact.

Another interesting difference between the HP device and the Motorola phone is that the Motorola phone operates on 802.11a. Motorola and Avaya spokespeople said they chose 802.11a because the networks can handle more capacity than the other flavors of 802.11.

Sales, which will be handled at least initially by Avaya and not a cell phone operator, might be challenging because the decision to implement such a solution is complicated. An enterprise would have to decide to potentially switch existing cell phone users in the company to whichever GSM operators may support the phone--the companies haven't said which may support it. It also presumably means that a company might grapple with feeling the need to sign up additional cellular users in an effort to standardize on the phone.

The decision also may be more complicated for enterprises that already have WLANs. This solution requires companies to either upgrade existing Proxim APs or deploy new APs, which will support both the voice calls and existing laptop or other handheld based data access. However, as part of this announcement, Motorola said it is forming an industry group to standardize such platforms so that end users might have the option of using different vendors. It will remain to be seen if other companies will be interested in following Motorola's lead.

The solution will be available some time later this year and it will be introduced with a carrier which has not yet been named.