We're not sure about this. Certainly, if they physically have your phone, they can get it to display its current lock status, but when you have the phone, we're not sure. It might be possible, in theory, for them to interrogate the phone through the cell service control signals, and get the phone to advise of its status, but we've never heard of this being done.

In areas like the United States where carriers offer free or deeply discounted phones with cell plans, the phones are commonly locked so that they will not work with other carriers. Carriers claim this is necessary to subsidize the cost of the phones. After a period of time, a carrier might agree to unlock the phone upon request, perhaps charging a fee.

We used to think the answer to this was 'no, of course not'! But then a reader wrote in to tell us how he bought a Treo, new and unlocked, and after using it with T-Mobile, changed his service provider and started using it with AT&T. To his surprise and horror, AT&T somehow then locked his Treo and now are refusing to unlock it, even though he never bought it from AT&T and never let them touch it. Somehow they apparently sent a locking signal to the Treo that locked it to their SIM.

If the contract is more than a year old, you should be able to cancel it by giving a month's notice. If your contract has some time to run, advise us of the expiry date and we will contact you nearer the time.

All that's needed is a SIM chip from an old phone that already has service. The SIM chip is usually installed in a socket behind the battery. Simply slide the chip out of the old phone and slide it into the same type of socket on the new phone, taking care to align the diagonal notch with the notching around the socket. The existing service - including the phone number and associated calling features - is now transferred to the new phone.

We believe that you should have the right to use your pay as you go phone on any network you choose. We do not believe that you should not be allowed to insert another sim card into your phone and be locked out by your original service provider. Also if ever you want to sell your phone its value will be increased if it is network unlocked.

Short codes must go through an approval process with each individual service provider. We have agreements with most of the major carriers and as we launch this new service we are still working with other providers, such as T-Mobile.

GSM is a type of digital mobile phone service. The more common type of digital mobile phone service in the US is CDMA, but just about every other country in the world uses primarily or only GSM. For you as the user of your phone, there is no difference at all between using a phone on a CDMA system or a phone on a GSM system. Unfortunately, the two different systems are not compatible with each other.

Most VoIP Service Providers now offer the option to keep your existing phone number if you wish (referred to as number portability). This may vary between VoIP Provider, so check this before signing up for service. This type of information can be found under the Plan Search page for your convenience.

For your own convenience, we recommend that you get a mobile (cell) phone. It's cheapest to buy it in the UK because that's where you'll be making most of your calls. The easiest way for students new to the UK to get a phone is to use a 'pay as you go' plan. You purchase the phone (?30 - ?300), select a service provider and then buy top-up vouchers that allow you to add credit to your phone.

Regrettably we can’t make calls to these at the moment. So please don’t give us your mobile/cell phone number as a contact.

When you subscribe to 4XFindMe, you are also able to set up your cell phone to receive alerts. Mobile/cell phone alerts are optional, but recommended to ensure you never miss a trade.

I am looking at buying 1995 Beneteau 405 from charter fleet. I would like to get your opinion of the boat and also any problems you may have had.

In most cases, your wireless carrier will allow you to use your minutes without activation of a data plan. You maybe able to take advantage of any free evening/weekend minutes that maybe available as part of your plan. Please check with your carrier for their updated pricing plans for minutes or megabytes.

The short answer is “it depends on where you travel in the region”. A few years ago, when all cellular networks were analogue, every carrier used the same technology; as long as your provider had a roaming agreement with other carriers, you could use your cell phone almost anywhere there was cellular coverage. Now that the cellular industry has switched to digital service however, there are two different types of technologies: CDMA and GSM, and they are not interchangeable.

Because you want to change the wireless company you get service from in the US, and want to keep your present phone. You've changed to a different service provider and got a new phone, but you want to unlock your old phone so you can use it in an emergency just by swapping the SIM over if your main phone gives problems.