By Oo Gin Lee

ALL THREE mobile VOIP ( Voice over Internet Protocol) services offer two basic propositions - call another user on the same service for free (like good old Skype to Skype) or call any phone number at competitive rates.

If you call using Wi-Fi, you don't incur any additional access charges, but if you are using 3G or 3.5G, remember you have to pay for data access as well.

Mediaring and pfingo both make use of a standard called Session Initiation Protocol (SIP) which enables voice and video communications between multiple parties over the Internet.

SIP has become the de facto standard for the VOIP industry, but Skype uses a different proprietary system. The reason why Nokia N and E series phones are the ones which work with pfingo and Mediaring is because these phones have SIP built into the phones and are able to accept SIP profile updating over-the-air via SMS.

Because SIP is the industry standard, phones with built-in SIP work easily. To get started on using pfingo and Mediaring to make calls, you simply need to click a link at their website. You then receive an SMS in your phone.

Open it and it automatically configures your phone to use the service. It's the same like the way you set the settings on your phone to get Internet access.

For Skype, the set-up takes more time as you need to download the Skype application into your phone.

The voice quality for all three services were good, though occasionally I experienced some lag after speaking for a long while. Topping up credits is also easy, just go to the respective websites and top-up via your credit card.

Be careful about using these service when overseas because the data roaming fees, if you are using 3G, will knock you senseless.

Mediaring Mobile

Getting started: Go to www.mediaring mobile.com. Check that your phone model is supported. Sign-up for a new account and click to request for the SIP profile to be sent to your phone. Once your SIP profile is set-up, key in the number you wish to call.

But instead of pressing the green "call" button, press Options then select Internet Call. That tells the phone to connect your call via VOIP. You can still make and receive your normal phone calls the same way you would use it.

Why it's cool: Mediaring has been in the wholesale voice business for many many years and has built a formidable network which results in very competitive IDD rates.

The website interface is easy to follow. Whenever you make a call, you hear a voice telling you the credits you have left in your account and what that translates to in terms of talk time.

How it could be better: Unfortunately, Mediaring does not issue a prefix-3 number, so your recipients will not be able to see your phone number when you call them. Also, you cannot send or receive SMS messages. It's easy to use, but it also has no bells and whistles.

Verdict: A simple no-frills service that gets the job done.

pfingo

Getting started: Go to www.pfingo. com. The procedure is similar to Mediaring except that pfingo also offers you a software called pfingo mobile which you can download into your phone.

You can install both pfingo and Mediaring into your phone. To switch services, go to Menu, Tools, Connectivity, then Internet Tel.

pfingo mobile offers a suite of extra applications in your phone. You can get push mail, online calendar and even an integrated mobile chat service in which you can combine your Yahoo, MSN, Google and ICQ accounts into a single chat window. It also lets you send a Web SMS which your recipient can also reply to.

Why it's cool: pfingo has an $11 unlimited package for unlimited local calls. It also issues a free prefix-3 phone number which your friends using the normal land and mobile lines can call you on. That means your number appears on your friend's caller ID when you call them - like any normal phone line.

With integrated chat, Web SMS and even a profile page that tells you the credits you have remaining, as well as your data traffic used, pfingo offers plenty of useful extras.

How it can be better: Because pfingo offers so much more, navigating the website is a little more complicated. The SMS system is also limited because your friends cannot initiate an SMS message to your phone directly, they can only reply to your SMS. Your friends are actually responding to a GSM modem which pfingo then forwards to your Web SMS account.

Verdict: The best value for money.

Skype

Getting started: Point your phone browser to http://www.skype.com/download/skype/windowsmobile/download.html.

Click on Download Now under Skype 2.2 for Windows Mobile. If the file fails to install (which happened to me) choose the Advanced User option and download the .cab file directly. If you already have a Skype account, just log in as usual and make calls by simply keying in the country and area code followed by the phone number. So, to call Singapore, key +65 followed by the number.

Why it's cool: With one million users in Singapore alone, Skype is the most installed and most popular VOIP software. That means you have a good chance of calling your friends for free. Skype's mobile interface is easy to use and feels just like the desktop version.

Skype now has the World Unlimited service where you can call phone numbers in 34 countries for US$12.95 (S$18) a month, or you can choose the single country service and pay US$5.95 for unlimited calls to Singapore landline and mobile numbers.

How it can be better: Since Skype is proprietary, it is only limited to Windows Mobile phones for now. Set-up is harder compared to the SIP-based services and longer because you have to download an application. The biggest gripe however, is that you need to use a earpiece to be able to talk on Skype mobile.

Verdict: The best rates with Skype Unlimited but it feels more like running an Internet application instead of making a phone call.

This article was first published in The Straits Times, Digital Life on 24 June 2008.

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