* Early dual-mode services reported
Rumors were rampant last week that T-Mobile had stealthily begun beta testing a dual-mode service that allows your cell phone to make calls on the carrier’s GSM network and over your home Wi-Fi network, all for one flat monthly fee.
Alleged T-Mo beta testers leaked photos of T-Mobile-branded dual-mode Wi-Fi/cellular handsets (unmasked as the Samsung T709, which is scheduled to commercially ship late this year or early next). The packaging and information indicate that the mobile network operator is poised to become the first nationwide U.S. carrier to offer internetwork wireless roaming for voice calls, targeting the residential sector first.
Beta customers reportedly install a wireless router similar to that offered by your wired broadband carrier for also supporting Wi-Fi connections to your wired Internet connection. These routers, however, handle the handoff between Wi-Fi and GSM signals using a technology called Unlicensed Mobile Access (UMA), an emerging 3GPP standard and one of several approaches to enabling convergence across disparate wireless networks.
The system uses your existing cell phone number and infrastructure while enabling Wi-Fi calls and reportedly aims to be the final nail in the coffin for wired phone usage in U.S. residences. Many folks now, for example, retain wired phones in their homes because their cell coverage is iffy.
Said one blogger, for example: “I have no cell phone service in my house. If the phone [rings], I have to….run outside like a crazy person to keep the call. I’d gladly use my own Wi-Fi connection to have a single number in and out of the house.”
A single voicemail box completes the “unified” picture. This differs from, say, running Skype or other IP telephony client on one of today’s few dual-mode cellular-Wi-Fi handsets. Those setups don’t innately provide handoff capability, so there is no inherent roaming across the Wi-Fi and cellular networks. Rather, you must use the Wi-Fi network (at home, attached to your ISP connection) or the cellular network with different service providers, voicemails, and bills.
No word from T-Mobile on particulars.
For its part, competitor Cingular Wireless says it expects to be selling dual-mode phones “by next year” once its IP Multimedia Subsystem (IMS) infrastructure from Lucent is in place. The carrier says it is “looking at both business and the consumer.” IMS is an alternative convergence technology to UMA.
Verizon Wireless, which has announced plans to use Advanced-IMS (the technical details of which are sketchy) for convergence, says it is studying dual-mode services, too. Both Cingular and Verizon said they are evaluating voice QoS issues as they relate to the interference-prone unlicensed Wi-Fi spectrum.
