Truphone Anywhere might sound very clever, but all you really need to know is that it can save you money on international calls.
When you are out of range of a Wi-Fi connection, you just make calls as usual (there's no separate application), and Truphone Anywhere gives you the option to route as much of the call as possible over the internet. Simple.
You'll be asked each time you dial an international number whether you want to use Truphone Anywhere (you can turn this question off in the settings once you are comfortable with how it works).
Truphone Anywhere can save you loads of money on making international calls from your home country if you have a deal that includes 'free' or low cost bundled minutes for domestic calls (which many of you do!). If you are a European pay as you go customer, or have an international discount pack, you'll have to study your tariff more carefully to determine where you can make savings.
Truphone Anywhere works in two modes: call through and call back, but all the clever behind the scenes stuff happens automatically. Calls made with Truphone Anywhere behave like all other calls - you just dial as normal and wait for the call to connect.
Call through is the default mode of operation. It's brilliant for making international calls if you have 'free' or low cost bundled minutes to make calls in your home country included as part of a monthly fee.

If you dial an international number, the call is redirected at the handset to a Truphone access number in your country, which connects to our server which in turn automatically completes your call to the international destination. (We play you audio prompts so you know how the call is progressing, and we make sure the handset call log shows the originally dialled number.)
In this case you may be using 'free' or low cost bundled minutes for the first leg of the call and Truphone's low international rates for the second leg. This is often much cheaper than the international rates charged by other mobile operators.
Call Back is for advanced users. It can be useful both at home (if you are on a high cost pay-as-you-go tariff) or when travelling abroad.

(Be reassured, all this technical wizardry happens behind the scenes. You just dial and wait for the magic to happen!) When you make a call (to an international number or any number when you're roaming abroad) the handset automatically sends an SMS text message to our server (in the UK or USA) requesting the call. It then calls you and also places the onward call.