AT&T said on Monday it has started offering its enhanced push-to-talk (PTT) services on the iPhone 5 and 4S through an iTunes app, though it’s only available to Ma Bell’s business customers for now. For those of you unfamiliar, push-to-talk functions like a walkie-talkie radio, allowing you to instantly communicate with a similarly enabled phone, rather than initiate a phone call. The service was a big selling point on Nextel, and later on Boost Mobile, particularly popular with blue-collar workers and the younger crowds.

Other operators have launched their own IP-based PTT applications, but they’ve been able to match Nextel’s success, largely because of the peculiarities of the iDEN. Motorola used its public safety communications expertise to build PTT directly into the iDEN’s core infrastructure. That close integration meant Nextel’s service routinely beat out its competitors in call set-up times and call quality.

But on June 30 that network goes dead, which has led many carriers and developers with competing PTT apps to put their services forward as alternatives. Sprint offers its own CDMA-based PTT service, called Direct Connect, and managed to lure many of its Nextel and Boost subscribers over to the Sprint side of the business. But at last count Sprint had 1.3 million iDEN customers remaining. Other operators probably feel the playing field is being leveled, making this summer the perfect time to go after PTT users.

Whether AT&T’s iPhone support will lead to a big boost in customers using PTT remains to be seen. While the iPhone isn’t exactly the ruggedized handset you’d expect to see used by construction workers and field technicians, the iPhone has become popular in almost every mobile circle. With bring-your-own-device (BYOD) trends gaining steam among enterprises, this could be a good way for businesses to hook one of the most popular phones among their employees to their PTT communications networks.

AT&T also announced on Monday that all PTT users will now be used over Wi-Fi connections, including its 32,000-hotspot Wi-Fi network. Wi-Fi support means phones can take advantage of stronger WLAN signals indoors, increasing chances of establishing and maintaining a PTT session.

This won’t be the only iPhone news we’ll likely see today. Apple’s WWDC is kicking off right as this post goes live.

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Sprint's iDEN network in New Orleans. The dark towers are slated for decommissioning

According to 4G Rollout, New Orleans is the first market on the list with its initial cell sites scheduled to go offline in February shortly after Mardi Gras. Sprint is going to gradually phasing out iDEN so New Orleans Boost and Nextel customers won’t emerge from Fat Tuesday hangovers with no service. But Sprint will pack up its base stations at multiple towers, while expanding nearby cells to fill the gaps.

The iDEN network is actually over-built, designed before the Sprint’s purchase of Nextel and the ensuing flight of millions of customers from its data-impaired networks. So there’s plenty of capacity left in Nextel’s urban networks to cope with a topological rescaling. However, any time you do this kind of network tinkering there will always be coverage holes. Some Nextel and Boost customers can expect their service to suffer, especially as Sprint gets into 2013 and starts shutting down sites en masse.

Outside of New Orleans, there’s not too much useful information since Sprint doesn’t appear to have identified any other specific cell sites scheduled for decommissioning. But you can click on individual sites in your city or town to see when Sprint plans to start its evaluation. For instance, in my city Chicago, all of the sites will likely be under review in June.

Sprint plans to use iDEN’s 800 MHz spectrum for supplemental capacity on its LTE network, which will launch mid-year. But the way Sprint is winnowing down iDEN that spectrum won’t be available until the full network goes dark. Sprint may be shutting down sites, but it’s still using the spectrum. It’s just covering more ground with fewer towers.

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I got some hands on time with WAVE Connections, a beta mobile application from Twisted Pair Solutions, and it could resolve both of issues that kept from using the phone as a push-to-talk device. For now the software only works on certain BlackBerry handsets and some older Windows Mobile phones, but since it’s a data-driven software solution, it could theoretically work on many supported platforms. Conversations are secured with the Advanced Encryption Standard (AES). And because it transmits voice as data, it can also work across operator networks ranging from 3G mobile broadband to Wi-Fi. You could potentially have a direct, instant conversation with a colleague on Sprint’s network from an AT&T handset, for example. Here’s how the company explains it:

WAVE Connections uses your device’s data network to connect you. WAVE software creates a virtual meeting in the internet ‘cloud’. Any device using WAVE Connections that is logged in and tuned to the appropriate Talk Group participates in the conversation. Because WAVE Connections uses Internet Protocol (IP) to create connections, it does not matter if there are 2 or 200 people on the Talk Group. In fact, the amount of traffic over the wireless connection for each device is the same regardless of the number of participants.

Since I don’t have a BlackBerry device, the folks at Twisted Pair Solutions shipped one over and walked me through the configuration process. For the beta, it was simply a matter of signing up and installing the software on the handset. A few other client settings were required, such as the WAVE Connections server, but if you can set up an email app on a mobile phone, you can certainly set this up. After that, I was off and running, or PTT’ing as it were.

Tapping a button on the side of the BlackBerry activates the microphone so that you can speak. Once you’ve said your piece, you release the button, just like a walkie-talkie. Sound quality was outstanding: better than a cellular voice call on a speakerphone, by comparison. I suspect that quality will vary based on the data connection, however, which can be highly variable. Of course, since this is a system where only one person can speak at a time, there’s some getting used to the timing of a two-way radio conversation. But once I had the hang of that, I found it to be an effective and instant communications method.

The WAVE software doesn’t just support two-person conversations, however. Within the online configuration, you can set up groups of multiple people: say, the entire GigaOM team in a GigaOMTalk group, for example. With the software we could then communicate by voice as a group at the touch of a button. Ideally, the solution is geared for field workers, but I’m reminded of a short list I put together last week comprised of smartphone applications for families. This solution, once out of beta and on additional platforms, would make a nice addition to that list, and could be used for family communications on vacation, at events or throughout the day as needed.

Thanks to software, voice as data and a cloud service to put it all together, WAVE Connections looks to have a promising future by bringing a new twist to an old communications method.

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