PUBLISHED : Monday, 14 May, 2007, 12:00am
UPDATED : Monday, 14 May, 2007, 12:00am

Some time ago, I read an article about a mobile phone that could take two SIM cards. Such a handset would be able to have a card for China and another for Hong Kong, as I understand it. Would that be the best way to cover both China and Hong Kong?

NN, Mid-Levels

DQ: The good and bad news about this - or, for that matter, almost any new technology - is that things change quickly. It is true that a few months ago a number of such mobile phones were advertised, but the technology has moved on.

The mobile service providers have finally recognised the needs of those who want to go to the mainland without having to take two phones and have been working on a solution.

If you pop across the border to Guangzhou or Shenzhen, you could be forgiven for thinking you have entered a world where Batman is a fashion icon. A number of busy-looking people seem to be wearing utility belts that resemble the one worn by the caped crusader. But instead of being loaded with bat-themed gadgets used to fight crime, these belts are festooned with mobile phones, PDAs and even pagers. It's a great look for a teenage boy but hardly suitable for time-poor businessmen.

There are a few ways to achieve the coverage you desire. Not long ago you could buy a subscriber identity module card-cutter and try cutting up a SIM card and putting two into your phone.

I can't imagine many people doing that today. Buying a phone that can take two cards is also passe. Instead you should apply for a special service from your telecommunications company. In Hong Kong, a number of operations - One2Free, 1010 and others - offer services that will get you up to five numbers on one SIM card. Billing is made easier, too.

On the mainland, some companies even allow your two phone numbers to have the same last eight digits.

The Hong Kong number would begin with +852 then xxxx yyyy, while the mainland number would be +86 139 xxxx yyyy. That certainly sounds like a plan.

Besides needing only one handset, you can receive text messages a lot more easily. I know people who have two mobile phones and get only voice calls - but not text messages - when they divert their Hong Kong number to their China number. Having a multi-SIM service would fix that.

Remember to study the small print when it comes to promotions for multiple numbers. Check your last few bills to see how much you are spending on roaming and other services. It may be that roaming is sufficient on its own.

But if you do travel enough to justify it, a multi-SIM service could be what you are looking for. You will need more than one battery and possibly a charger that can be plugged into a variety of power sockets.

Ask your mobile carrier if it has, or soon will have, such a service.