By Jo Twist
BBC News Online technology reporter
The sound of mobile ringing tones could be in for a big change if a new service proves as popular in Europe as it has been in South Korea.
You could soon be saying goodbye to dial tones
Korean firm WiderThan's service lets you choose what the person calling you hears when phoning.
"It replaces your normal dial tone with music or any kind of content you want," said WiderThan's Jonathan Kim.
The service has been very popular in South Korea, and could be offered by European mobile networks by mid-2004.
Launched 15 months ago in South Korea, the ring-back tone or tone replacement service, called Coloring, has made SK Telecom $100 million (£59 million), with 35% of their subscribers using it.
"It is definitely popular with teenagers," Mr Kim, vice president of global marketing, told BBC News Online.
"But we have also found as the product matures a bit, it is popular with those in their 20s and 30s and even older users are using it" .
The service has been as big a hit as voicemail was when it started.
It is going to be huge with those keen to spice up their mobiles when it hits Europe next year, forecasted Simon Buckingham from research firm Mobile Streams.
"I certainly think that the ring-back tone service is going to be very, very popular," Mr Buckingham said.
And he should know, because he is the mobile phone guru who made his fortune from text messages and ringtones.
"You have to take account local market requirements, but people want to personalise their mobile and this is a new way to personalise your ringtone inside the phone as well as outside it."
The main difference will be the way that people pay for it. In Europe, most people pay per ringtone download, said Mr Buckingham.
But in South Korea, there is minimal $1 subscription per month to pay, then ringing tones cost about 60 cents on top.
They are then loaded onto the network rather than the mobile itself so there are no problems with phone compatibility.
Through partnerships with 20 different content providers, and having negotiated the tricky license deals directly with music labels, subscribers can choose from an array of local and global hits from a library of 30,000.
"Unlike ringtones it is real music," said Mr Kim.
"It is almost like the operator becomes the DJ by picking the tune list.
"I could pick out the top 25 music hits and put it on a net environment and the user picks what they want."
It could mean new ways of buoying up flagging single sales for music labels, by offering bundles of mobile content for dial and ring tones, as well as mobile wallpaper of particular artistes.
Currently in trials with major European and US networks, the service should be available in Europe by next year.
UK mobile content providers, like Adviweb, are also getting in on the act by developing other types of personalised ringing tone replacement messages for mobile operators.
"Dial tone replacement will be very big, and we will just have to see how big," said Keith Buchanan, Adviweb director.
John Cleese sound-alike as a dial tone?
"It is going to be a different market in Europe than it is in Far East though."
Ringing tone replacement signals an evolution of the familiar ringing tone, according to Mr Buchanan, and another way to express personality and character through their gadgets.
"Our business is primarily humorous voice content which will much more applicable in Europe," he said.
Already in the personalised voicemail market, Adviweb will be provide ringing tone replacements using professional celebrity sound-alikes who will record bespoke messages ordered by mobile owners.
But, if this kind of service does take off as predicted, it might take a while for people to understand what they are hearing is not a voicemail message.
"It is basically a holding ring until someone picks up the phone," said Mr Buchanan.
"There has to be some way of communicating to the listener that it is just an evolution of the old style tone."
Ringtones, and polyphonic ones in particular, have generated millions in revenue.
The Mobile Data Association predict £70m worth of ringtones will be sold in 2003, up from £40m in 2002.