A big step for BYOD: Separate billing for smartphones is finally here

AT&T Work Platform is a major step toward separating work and personal communications in a sensible way

I know you've heard this one before, but this time it appears to be real: You can have employees' data and voice use for work separately billed from their personal voice and date use, even if they're on a different carrier than your corporate standard.

One of the corporate objections to BYOD has been the overhead of managing employee expense reimbursements or the added cost of paying their full smartphone plans to avoid the accounting overhead. (Some companies have taken the opposite approach: making employees foot the whole bill, though that's no longer legal in California, at least.)

That billing objection hasn't kept BYOD from becoming the norm at most companies, but it remains a sore point for many companies.

This week, AT&T announced its AT&T Work Platform service that promises to allow separate work billing for smartphone voice and data use. I was skeptical since previous announcements along these lines have always had a major catch: The employees must have their personal service on the same carrier as their company used. (The latest such not-really-BYOD announcement involved BlackBerry.)

That meant it wasn't really BYOD since the chances that all employees use the same carrier as their company is basically nil. Due to coverage differences and family plans, it's unreasonable to impose one carrier on all users. True BYOD means the employee chooses a compatible device and uses the best network for him or her.

I pressed AT&T on the requirements for employees to participate in its Work Platform, since the details it posted are very vague. The good news is that many companies -- if they use AT&T as their corporate carrier -- can use Work Platform knowing that many if not most employees' devices will be compatible. 

AT&T Work Platform has two components, and it's important to understand them to know whether Work Platform will work at your company.

The first component involves voice and text messaging. These are Internet-based services, so they work over any cellular network. They're what the telecom industry calls OTT services (that is, they're over the top of their networks).

You probably already use such services, such as iMessage, FaceTime Audio, Google Voice, Google Hangouts, BlackBerry Messenger, WhatsApp, and so on. Basically, AT&T is providing work voice and text services through its own apps, which has the benefit of providing a separate number and address for work communications.

The second component involves data services, meaning getting cellular network bandwidth. The calculation here is more complex because employee smartphones have to run on the AT&T 3G or LTE cellular networks to use AT&T's data bandwidth, rather than data bandwidth from the employees' carriers.

Most smartphones in the United States are tied to a specific carrier's cellular frequencies, so they can't connect to other carrier networks, even if they are unlocked phones. Verizon and Sprint use a different 3G technology (CDMA) than AT&T and T-Mobile do (GSM), so their radios are different and incompatible. For example, a T-Mobile phone may not run on AT&T's data network, or vice versa, despite using the GSM standard for 3G. It's all but a certainty that a Verizon phone won't work on Sprint's network or vice versa, despite their common use of the CDA standard for 3G.

Worse, carriers use different frequencies even when they support the same technology (GSM, CDMA, or 4G LTE), deepening the incompatibility. U.S. carriers intentionally select different 3G and 4G frequencies from each other to create incompatibilities that they then require the smartphone makers to implement in the radios.

Still, there's been some loosening of these artificial incompatibilities in recent years, driven mainly by non-U.S. regulators that require compatibility across carriers for roaming purposes and the move to LTE as a universal 4G standard (though its spectrum remains incompatible across regions of the world).

Apple has taken the lead in deploying multicarrier radios in its devices, so one iPhone 6 model can run on the AT&T, T-Mobile, and Verizon networks, whereas another model can run only on the Sprint network (and the Japanese networks run by Sprint's Japanese owner, SoftBank). Sprint won't let its phones work on other U.S. networks, though their radios support the AT&T frequencies. Older iPhones are less cross-carrier-compatible, and few Android smartphones support multiple carriers.

However, if a smartphone supports multiple carriers for 3G or 4G data connections, chances are it will support AT&T's network. The reason: AT&T uses most of the same 3G frequencies as the rest of the world, so a "world phone" is AT&T-compatible as a by-product. However, just because a phone is compatible with AT&T's frequencies doesn't mean another carrier has to permit its phones to work on the AT&T network. In the United States, Verizon will do so only after you've paid off your phone -- and Sprint won't do it at all. T-Mobile doesn't impose such restrictions, but few T-Mobile-provided phones have the radios to support AT&T's network.

With AT&T Work Platform, companies will be able to easily separate voice and text usage for work from that used for personal purposes. That's more valuable than splitting the billing because it creates a real separation for compliance purposes between work and personal communications.

But companies will still have to deal with the issue of dividing the data access costs. Those expense reports won't go away for most employees. 

The top three multiplatform mobile device management (MDM) vendors -- Good Technology, MobileIron, and VMware AirWatch -- can provision and manage Work Platform via their MDM servers. That should smooth the path for enterprise adoption.

Although there are still network barriers that limit the data separation promised by AT&T Work Platform, I have to give AT&T credit for making this move. It's a major, positive -- and necessary -- change in the carriers' usual lock-in attitude.

Copyright © 2015 IDG Communications, Inc.