Within the last year or so, the idea of VoIP services running on a mobile phone, that use Wi-Fi and the Internet has been given a lot of coverage. So much so, that there is now a bit of a backlash against it.

It's all very well using Wi-Fi on a phone to connect to the Internet, but it needs a dual-mode handset, to connect to Wi-Fi and fall back to GSM or 3G when that isn't available. Otherwise, you are stuck with a Wi-Fi-only handset such as Vonage's UT Starcom F1000, which does its best, but is awkward.

So far dual-mode phones have been thin on the ground, although Nokia's E-series is starting to make headway in the market.

Another drawback cited against mobile VoIP is the danger that Wi-Fi will drain the batteries of a phone, making it less useful for calls. This was cited at the recent launch of RIM's Blackberry Pearl, and Palm's Treo 750v, neither of which included Wi-Fi.

Finally, it is expected that Wi-Fi services will be awkward to use, as users may find they need to authenticate to a new Wi-Fi service every time they use the phone, and on some machines, it is expected that they will have to use different dialler software, perhaps a softphone such as Cicero.

Making it easier?
The Truphone service, announced in May, promises to break down a lot of these objections. While still in beta, the service is being marketed, and does indeed go a long way towards this. One or two drawbacks remain, but the service is a very credible demonstration of the power and potential of mobile VoIP, and already provides a usable service with attractive introductory rates.

At the moment, the software runs on Nokia's Symbian-based E-series phones, which Truphone describes as the first "mass market" dual-mode handsets. We tried the software on an E61. It costs around £250 SIM-free, including VAT, and can be "free" when subsidised by a monthly contract, from sites like Expansys. The Truphone service can be used whether or not the device has a SIM installed, but a SIM is necessary during installation.

Installation was not exactly a breeze, but was do-able. Originally, we were sent a handset with Truphone pre-installed, but we managed to break the installation. This gave us a chance to see the installation process (and we should say that, after, re-installing, the set-up has been rock-solid).

To get the Truphone software installed, we sent a text message to Truphone and received a link back by text. We had previously connected the phone to our Wi-Fi access point, so it was easy to click the link and download the software. It installed easily (the process is described on the Truphone site), with most steps involving the acceptance of various agreements, or acknowledging various statutory warnings. One small process put the Truphone logo on the home screen of the phone.

During setup, we were given a phone number and a password to access our settings at Truphone's website.

The user experience
Assessing the Truphone experience is slightly tricky, thanks to its close integration with the Nokia phone. We were new to the E61's idiosyncracies, and stumbled over things that would be awkward with any other software.

The software comes with two "fixed" access points ready to set up - "Home AP" and "Office AP". There's also a "Travel AP" to work with new access points. The software uses the Nokia's Wi-Fi software to scan for and find access points, then link to them. Truphone can then save them as the Home or Office APs you will use regularly. The software can be set to automatically connect to these APs when they are available.

Adding an access point is pretty easy. The Nokia software scans for it, and then it is a matter of adding any security settings. For WEP and WPA sites, this means finding and entering a key. There are multiple layers of menus within the Nokia, but they become fairly clear with practice.

For password protected sites, this means opening the phone's browser and entering a username and password. The home and office sites remain in the system's memory and it can be set to log into them whenever it finds they are available.

Once registered, an icon on the phone's home screen changes, to show connection is available. We could then dial calls using the phone's keypad, and the green key to open the call. When Wi-Fi and GSM are available, there can be an extra step, choosing whether to make a cellular or Internet call.

Does it work?
We found that Truphone was very usable, and gave good quality, comparable to the phone's native GSM dialler. Once our home and office APS were loaded, it reliably roamed to them whenever they were in range, and remained attached, allowing Internet calls throughout the house. The office AP we used was equally welcoming.

Internet calls are made exactly the same way as ordinary calls. If there is Wi-fi, the phone prompts you to choose whether to use the Intneret when available.

When travelling, we found we more often used hotspots that required a password entered in a browser. This was actually quite fiddly, as it meant navigating across a web page on a small screen.

To our surprise, battery life did not bother us. Most of the time, we used the phone without a SIM card, so that reduced the power demand, but in fact, (and this may be a point for a review of the E61 phone) this phone seems to have tamed Wi-Fi, and give decent battery life.

We made free calls from a Vodafone Wi-Fi hotspot in a hotel in Portugal, to landlines in the UK. These calls were very clear, and were continued while we walked around within range of the hotel Wi-Fi.

In fact, Truphone came up trumps on that foreign trip as, the day we left, our ISP decided to cut off our home broadband and phone. Calls to our ISP's customer service were free from the hotel Wi-Fi, and continued for up to an hour without loss of signal. Unfortunately, they also were continued without our ISP actually answering them. However, this made a reasonable test of the battery life, which (unlike our ISP) did not let us down.

Free mobile calls from abroad are an excellent reason for using a service like this, and extent to landlines in fourty countries at least till the beginning of 2007. Calls to other destinations can be bought with pre-paid credit at rates that compare well with VoIP services such as SkypeOut.

The usability issue is perhaps more contentious. Entering a WEP or WPA key is not a big deal for us, and the phone is set up so that they only need entering once. However, entering a WEP key may be more technology than the average user wants - although Truphone has smoothed the process as much as possible, and regular APs need only be entered once.

On balance, anyone with a phone that can use Truphone (basically, the Nokia E-series) should give it a go. When it moves from beta to a full version, in the new year, it will be interesting to see if the pricing and usability change, but it's already a service we'd happily use regularly.

OUR VERDICT

Anyone with a Nokia E-series phone and Wi-Fi in their home or office, should try Truphone. Business travellers who know they have free Wi-Fi where they are going to should consider it, even if it means changing their phone. This service does a lot to make us believe in mobile VoIP, thanks to good integration on a decent phone platform.