UMA: Routing your BlackBerry calls over Wi-Fi

A quick recap for those who haven't read the previous columns: UMA allows you to route your phone calls over Wi-Fi, but unlike other VoIP solutions it's tightly integrated into the mobile network, so incoming calls to your normal mobile number are routed via Wi-Fi, and likewise your outgoing calls appear to the recipient as coming from you rather than some obscure VoIP provider.

Neither will their texts, data or BlackBerry-specific stuff such as PIN messages, because unlike traditional VoIP services UMA has these covered too.

You can just pitch up somewhere with zero mobile coverage and still be able to use all the normal functions on your phone, and the best thing about UMA is that there's nothing else to buy - so long as you have Wi-Fi and a phone that supports UMA.

The factory as part of the provisioning process

This is normally done at the factory as part of the provisioning process, and UMA-compatible phones supplied by Orange should already be UMA-enabled.

However, if you buy an unlocked phone from somewhere like eBay, or even an off-the-shelf phone from certain independent shops, it might not have the right internal settings. My advice if you're thinking about using UMA is to make sure the phone comes in an Orange box, and (for most phones) has Orange branding.

The device is set up for UMA

For BlackBerry phones it's easy to tell whether the device is set up for UMA by going to Setup | Options | Mobile Network - if you see an option on that screen between Data Services and Mobile Network that says "Connection Preference" then you know the device is UMA-ready. If you don't, it's possible to "hack" the phone to enable UMA, but it isn't a task for the faint-hearted.

If you look at that Connection Preference setting you'll see that it has four options: Mobile Network Only means that UMA will be ignored and all texts and phone calls will go over GSM or 3G; Mobile Network Preferred means the phone will try to use the mobile network but if it can't get a reliable signal it will fall back to UMA (assuming there's a Wi-Fi signal); Wi-Fi Only does pretty much what it says, so the phone will ignore the mobile network; and finally Wi-Fi Preferred will use UMA if there's a Wi-Fi signal within range, if not it will use the mobile network. This last is probably the best setting for most people.

How does this interact with the extortionate roaming charges levied by networks? Given a UMA connection in the UK is charged exactly as a UK GSM connection but is routed over the internet, what happens to a UMA connection in (say) the US? Does Orange deny the connection on an IP geolocation basis, even though technically there is nothing to prevent it working flawlessly? Does Orange charge it as a normal UK GSM call (as it should, given there is no marginal cost to Orange over a UK UMA connection)? Or does Orange use IP geolocation to implement a flagrant price gouging strategy where they charge US roaming rates to connect over UMA from the US?

Paul is a contributing editor to PC Pro specialising in smartphones, mobile broadband and all things wireless. He's technical director of a combined IT and marketing company, which works on websites and intranets for several blue-chip clients.