The following steps will pair the Sunglass headset with a Bluetooth-enabled phone:

1. Charge the Sunglass headset for at least 3 hours before using it.
2. Press and hold the power button on the headset until the indicator light blinks alternately from blue to red (about 15 seconds). This puts the headset into pairing mode.
3. Follow the phone's procedure for discovering new Bluetooth devices. Consult the phone's manual for instructions.
4. When the phone asks for a passcode or PIN, enter 0000 (four zeros).

Yes, all our GSM mobile phones are FACTORY unlocked - they will work with any GSM SIM card from any country on earth - so you needn't be tied into any specific carrier or contract. Every time you change the SIM CARD the GSM phone becomes whatever the new SIM CARD is. I.E. a new telephone number, memory for credit, the ability to work in the new country etc.

Cell phones purchased from wireless carriers or with wireless service are locked to the particular carrier, meaning that you must use that carrier's service for placing and receiving calls. Since ours are unlocked, you are free to use any wireless carrier that uses GSM technology. Most carriers worldwide use this technology. In the U.S., AT&T/Cingular, T-Mobile, and many smaller carriers do (Verizon and Sprint/Nextel do not).

Consider three possibilities and correct if appropriate:

1. A damaged SIM card.
2. The SIM card is not installed correctly. Ensure that the SIM card is inserted into the correct slot, with contacts facing the contacts on the phone, and the diagonal notch on the card aligned with the notching on the phone's SIM socket.
3. The SIM card is not supported. Please contact your SIM card provider.

The following possibilities may underlie issues connecting to a cellular network:

1. An invalid SIM card. Please contact you're the SIM card supplier to ensure the card is valid and working.
2. The phone may be out of the carrier's GSM service area. Consult the carrier's service map.
3. Weak signal. Attempt to reconnect when in an area with a stronger signal.

Please make sure that:

1. Your Cell Phone battery and charger should be available.
2. The ambient temperature is between +14°F and 131°F (-10°C and +55°C).
3. The charger plug is in a good condition and is well seated in the oulet.
4. For cell phones with external battery charging trays, the battery should be well seated in the charging tray, with battery contacts aligned properly to the contacts on the charger.

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.

The old phone can no longer be used, unless new service is established for it, since two cell phones may not have the same phone number.

Ordinary cell phone service works so that the unique serial number in your phone (its ESN) is used by the cell phone service provider to identify who you are. The wireless service 'knows' that a particular phone's serial number is your phone and knows to send phone calls to that phone when someone dials your phone number.

A GSM phone is not directly linked to you. Instead, it has a removable account card, called a SIM (subscriber information module) and this SIM has a unique serial number on it. This is what identifies you to the wireless provider.

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.

If you have a T-Mobile, Cingular, or recent new M-mode type service with AT&T, then you have GSM service.

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.

And, in any case, read the next two questions/answers for further reassurance on this topic.

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.

If it is your phone, you can legally unlock your phone as it is that you can give it away, lose it, break it, leave it turned off, or do just about anything else with it!

Unless your phone service contract says 'this phone remains the property of us (the service provider) and you agree not to modify or alter it in any way' then there would seem to be no reason why you can't legally do anything you like with your phone, so long as you're not attempting to defraud anyone.

It is illegal, in some countries, to change the phone's IMEI (serial number) - this is a type of what is called 'cloning' and, particularly with non-GSM phones, could enable you to then pretend to be someone else and have your airtime charged to someone else's account.

We don't provide any cloning type service and don't approve people to do so. But we do help you simply unlock a phone that belongs to you so you have freedom of choice as to which service provider you use it with.

Easy. Borrow a SIM from a friend who has an account with a different wireless service provider and see if it works in your phone or not. If it works, then your phone is already unlocked.

But if it creates some sort of error message and doesn't work, then your phone is locked.

There are two main companies that offer GSM service in the USA. AT&T and Cingular are now merged into one company, and the second company is T-Mobile.

If your service is with, eg, Sprint, Nextel, Verizon, or just about any other US wireless company, then you do not have GSM service and your phone can't be unlocked.

GSM service is offered in 207 countries.

Check this website to see if the country you are interested in has GSM service, and, if it does, what frequency the GSM service(s) operate on.

No. Once your phone is unlocked, it remains permanently unlocked, no matter what you do to it, unless you specially program back the lock code into it.

Yes, your existing service will work perfectly with no change, as long as you leave your present SIM in your phone.

Maybe. Your current wireless provider will still charge you exactly the same as before for all your calls.

But because your phone is now unlocked, you can use a different SIM from a different provider whenever this might give you better rates - for example, when traveling overseas.

There are three main reasons why you might want to unlock your phone.

• 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.
• Because you want to travel internationally and don't want to have to pay the very expensive international rates your present wireless company would charge you while internationally roaming.