Ever since RIM introduced the Blackberry in 1999, the desk phone has been targeted as a sunset technology. But 13 years later the desk phone is as ubiquitous as ever. Telephony vendors will post double digit gains for desk phones this year and projections are just as bright.

Still, businesses want to reduce communication costs to a single-call control environment. Employees have many ways to communicate and the desk phone--when not integrated into a larger platform--requires separate maintenance, support and bandwidth. And for added expense employees get multiple phone numbers and voice mailboxes.

Companies such as Cisco, Avaya, and Microsoft as well as the major carriers are unifying communication technologies under a managed platform. Unified communications (UC) reduces the relevance of the desk phone as just another way to connect with customers and colleagues. It's in fact a decreasingly common way to connect. A Pew survey showed that 31% of adults would prefer a text message over a phone call on their mobile device. And that's where it's trending. Teens now send or receive more than 3,300 texts a month.

Though it's strictly top-down deployment, UC builds in a BYOD spirit because it gives employees multiple options to interact with customers and colleagues.

There are a number of alternatives to a standard desk phone and infrastructure. There is a strictly cellular solution where the infrastructure is mostly outsourced to the cellular carrier. The greatest challenge says Brandon Hampton, director at Mobi Wireless Management, is the cell phone coverage within the building. The carrier's signal attenuates substantially the further into a building the signal has to travel. A poor signal requires an internal antenna to augment the outdoor coverage, an expense carriers won't necessarily cover. "A lot of times it's depending on the carrier and how willing they are to help you to either finance or install it. Some are more willing than others," said Hampton.

Ironically, for businesses that rushed to embrace BYOD--where each employee chooses his own phone and carrier--creating a PBX-like solution through the carrier is nearly impossible. For it to work the organization would need to consolidate to a single carrier and take ownership of the phone number, creating still more overhead for IT. And that's if the employees would tolerate it.

This solution would work best for businesses that are using an old PBX and provide cell phones to employees on the same carrier, or a startup that has no investment in a phone system.

The solution is impractical for businesses that recently invested heavily in an Avaya One-X Mobile Server, Cisco Mobile 8.5, or other IP platform. But many of these manufacturers have also built iPhone and Android apps to extend the network to the smart phone.

The apps allows employees' self-provisioned smart phones to work within the IP phone network. Cisco's Mobile 8.5 platform incorporates the infrastructure of a corporate Wi-Fi. Employees can make and receive calls both in the office and through a VPN where they find a strong Wi-Fi signal. Avaya users can decide whether to dial with the app for business calls or directly from the iPhone for personal calls. Using the app gives a caller ID as if it were a corporate call initiated from the desk phone.

Lync is Microsoft's UC strategy to manage all employee communications mechanisms, including voice, IM, and video. It replaces the old corporate PBX or extends existing IP telephony platforms from other vendors. Larger companies are simultaneously upgrading their telecommunications platforms with their desktop. So Windows 7, Exchange 2010, SharePoint, Lync, and mobile apps upgrade and integrate collaboration from a previously disparate set of products: Windows XP, Communicator, desk phone and voice mail, cell phone and voice mail.

For small businesses and startups, Skype for Business, with its cellular partners, Verizon, KDDI and Hutchison 3, offers small- and medium-size businesses Skype over 3G, but not Wi-Fi. Microsoft provides a Web interface to assign features and credits to users. It also easily integrates a soft phone by downloading the application to an employee's computer. You can transfer files, conference with colleagues, and make video calls. Again, you would need strong cellular coverage in the office as well as all working on the same network and it has some management issues.

Where is Apple? Apple's FaceTime will work over cellular networks in iOS 6. But Apple might have missed an opportunity to get iOS into the enterprise on the back end. In 2010 Jobs asserted that FaceTime would be an open industry standard. At the time, Lync--which was rebranded from Unified Communications and Collaboration--wasn't fully matured and Apple might have had an in. But today, even on Macs and iOS Skype is a better solution from a business point of view even though it has management limitations of its own.

Momentum carried the corporate desk phone this far into the 21st century and it won't vanish any time soon. One undersold feature of UC is that it provides businesses with detailed metrics on the use of each communications service in the enterprise. At some point, business will know when--if ever--it's not worth supporting the desk phone. It might be when those teens who love texting now enter the workforce and won't use a desk phone because it doesn't have smartphone features. At that point, years from now, when Windows 7 and Lync need a refresh, IT will finally cut the cord.