Softphones Reviewed: Global IP Solutions' REX

REX is specifically designed to function well in difficult environments—as in, over the public Internet.

By Jeff Goldman | Posted Apr 17, 2008
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When Global IP Solutions (GIPS) acquired CrystalVoice in January of 2007, a key VoIP technology that came with that acquisition was CrystalVoice's Remote Extension softphone. After the acquisition, GIPS rebuilt Remote Extension with a new user interface, and renamed it REX.

REX, which GIPS first introduced at Fall VON last October, began shipping in February of this year. According to Dovid Coplon, GIPS' director of product management, in addition to redesigning the user interface, GIPS added a significant amount of new VoIP-related functionality as well—including advanced presence, multi-party chat, voicemail, call forwarding, and more.

Coplon says the aim was not only to make REX a competitive softphone solution, but also to take advantage of the call management features, called Acoustic QoS, that were part of Remote Extension. "We're focused on two-sided call management, and we're looking for robustness in adverse network conditions," he says. "That's where GIPS sees its unique differentiation."

Company systems engineer Dan Hislop says REX can function either peer-to-peer with another REX client or through a server. "Our server handles the presence management and call setup," he says. "However, one REX phone calling another REX phone does not necessarily go through our server—we prefer for those two phones to talk directly."

In either case, Coplon says REX is specifically designed to function well in difficult environments. "Our NAT/firewall traversal technology is capable of establishing calls regardless of the conditions… and when there's a dip in available bandwidth, rather than dropping the call, we're going to drop from a wideband to a narrowband codec, and just try to use less of the bandwidth that has now become constricted," he says.

Clean and intuitive

With that in mind, we tested REX at VoIP Planet.com—across Jupitermedia's firewall, which has prevented some other softphone services from functioning well . . . or at all.

The installation process was simple: It's a 3.92 MB download that self-extracts and installs on a Windows PC with a few clicks. When you first open the application, you enter a user name and password, then run an Audio Wizard, which configures audio input and output levels. And then you're ready to place and receive calls.


REX user interface
The REX user interface
Click to see full-size image

The REX user interface (see image) is clean and intuitive. You simply click on a name in the contact list to connect to that person directly via either voice or instant messaging, (The Contacts tab also shows the presence of everyone listed.) To reach someone not listed in your contacts, you can either search for them via the Directory tab or simply enter the phone number on the Keypad tab.

In our tests, REX was able to traverse Jupitermedia's firewall successfully, but we had significant problems with voice quality—at first. After checking with the folks at GIPS, we were told that a misconfiguration of GIPS' server-side firewall was making REX measure network quality incorrectly, causing the Acoustic QoS technology to downgrade every call to narrowband.

With the configuration error corrected, call quality was significantly improved, though it still wasn't perfect: On test calls, the call recipient often said it sounded like a cell phone call, with the sound periodically fading in and out. Still, call quality was definitely far better than one would usually expect over the public Internet—and that's GIPS' key aim with REX.

Additional offerings

The REX solution also consists of two other components: REX Mobile for Windows Mobile handsets, and the REX SDK. In January, GIPS announced that Toktumi had licensed REX as the basis for its new small business phone service (see our first look).

"It's an excellent example of the use of our SDK, in that we're providing all of the call placement on the back end—we're doing all of those PBX-like features like the voicemail, the call forwarding, the auto-attendant—but it's Toktumi that is providing the service and the UI," Coplon says. "It gives them the flexibility to really build a service around our calling capability."

The point, Coplon says, is that the SDK gives you the ability to select any subset of the REX functionality that you might need, then integrate that your own offering. "For example, if you were to do a call center application, you might want to add calling capability into a database-driven system so you can understand the customer's help requirements," he says.

Looking ahead, Coplon says GIPS' next step for REX will be to add support for video. "We acquired a codec called LSVX just over a year ago, and so we have been adding multimedia to all of our audio products," Coplon says. "And the same will be true for REX—we're going to be adding video, probably at the end of the summer."

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