T-Mobile has reversed its ban on voice over IP — but only for customers on premium contracts.
The mobile operator banned VoIP in May this year "for commercial reasons" and said it would kick VoIP users off the network if they were caught. But this week it changed its data tariffs — and in the process partly overturned the ban.
T-Mobile has now introduced two datacard tariffs, one of which allows the use of VoIP, and one which doesn't. For £29 per month users can consume "unlimited" data through a combined 3G and Wi-Fi datacard, but aren't allowed to use VoIP.
Customers who ignore the ban will be warned, and could then see their connection speed slashed. "Network protection controls may be applied which will result in a reduced speed of transmission," warned T-Mobile on its Web site.
Only users who pay T-Mobile an additional £15 per month for the web 'n' walk Max product can legitimately use VoIP.
The new policy applies whether the subscriber is connecting over T-Mobile's cellular or Wi-Fi networks.
One catch is that "unlimited" doesn't mean unlimited. Users on the £29 web 'n' walk Plus tariff are limited to 3GB of data per month, while the web 'n' walk Max package gives a maximum of 10GB.
"When we didn't allow VoIP, there were two things. It was a pretty immature technology, and we had concerns over the user experience. It was potentially using up bandwidth, and we wanted to make sure that was done equitably," explained Robin O'Kelly, head of corporate affairs at T-Mobile.
O'Kelly confirmed that T-Mobile would now allow VoIP on the £44-per-month Max tariff, but warned that the quality might not be very good.
"I don't think it is a great user experience, but we [now] take the view that we don't want to stand in their [customers'] way. We haven't had a great demand for it, but some customers want to use it," said O'Kelly.
Margaret Hopkins, an industry consultant at Analysys, suggested back in May that T-Mobile had banned VoIP for commercial reasons.
"I'm not saying you can be sure of perfect quality on a VoIP network, but it seems to me that's not the main motivation for T-Mobile's decision," said Hopkins. "This looks to me like they don't want VoIP to affect their voice revenues."
T-Mobile's VoIP ban proved unpopular with a majority of ZDNet UK readers. In a Web poll of 452 readers, 74 percent said the mobile operator was wrong to ban VoIP.
Every other UK mobile operator allows VoIP over their networks, and 3 even actively promotes a partnership with Skype.
T-Mobile has also completely reversed its ban on instant messaging, which it introduced at the same time as the ban on VoIP. The mobile operator now ships PDAs with an IM client installed.
Many users install VoIP clients on their laptops and PDAs for convenience and to try to save on calling costs.
Calls over IP, particularly when abroad, can cost a fraction of standard voice charges.