GSM cell phones use a SIM (Subscriber Identification Module) card that stores subscriber data. The SIM card is issued by a carrier and provides cell service by activating any phone into which it is inserted.
A locked phone will only recognize a SIM card from a particular carrier. The "lock" is a software setting that keeps the cell phone "loyal" to one carrier.
Unlocked devices are cell phones that recognize SIM cards from any carrier.
Why do Carriers lock phones?
A locked cell phone will not allow users to change phones at their leisure. A locked cell phone benefits only the carrier by keeping a customer using their service.
Some cellular carriers require that you purchase a locked cell phone for the contract period, but will unlock the phone at the time that the contract expires.
Unlocked phones
give consumers more control of plans, pricing, and services and make carriers work for you.
Unlocked phones
give consumers the freedom to move your SIM card from device to device without signing another carrier contract. This means consumers can easily switch to a different phone whenever they want. This gives them more freedom if their device breaks or is damaged, or if they want to upgrade.
Some
unlocked phones
are sold directly by the manufacturer, not from the carrier. Sometimes carriers like to alter the phone to fit certain requirements. These locked phones can have alternative carrier software, or have missing pieces of the hardware, such as WiFi or GPS. Unlocked phones sold directly by the manufacturer are un-altered by the carrier, and don’t have any altered software or missing hardware.
Most cellular carriers require that customers sign a contract when they purchase a locked cell phone. Carriers subsidize the price of the phone to make an attractive offer, but require the customer to sign a contract so the lost revenue can be made up over the time period of the contract. However, if the phone is ever broken or lost, the customer must buy another phone, which the carrier usually sells for full-price. Unlocked phones are not subsidized, so they must be sold at full-price, yet the benefit is that the customer does not need to sign a contract or contract extension.
What are the
international benefits of unlocked phones?
International roaming charges can be quite expensive, exceeding $5.00 per minute for outgoing as well as incoming calls.
Unlocked phones
give customers the freedom to travel without paying for roaming. Customers with an unlocked phone can purchase a
pre-paid SIM card through Buy.com or in the foreign country they are visiting, and pay a fraction of the cost of roaming plus, in most countries, receive unlimited free incoming calls.
Another alternative is to use the phone as a VoIP device. With VoIP (Voice over IP), the phone makes phone calls over an WiFi spot with VoIP services such as Skype. There may still be a charge, but it is minimal compared to
international
roaming charges.
More Questions
Unlocked phones
can be used on any GSM network world-wide. Most networks in the world-wide operate on a GSM network. In the United States, the largest GSM networks are AT&T and T-Mobile. Unlocked cell phones will not work on CDMA networks, such as Verizon and Sprint.
I just bought an
unlocked phone ; how do I activate it?
Switching to your new phone is easy. Remove the SIM card from your current cell phone (usually located near the battery) and insert it into the new phone. Turn the new phone on (make sure the phone is charged). Your new phone will now send and receive phone calls with your original phone number. There is no reason to call you carrier.
I am in the middle of my carrier contract but I want to upgrade my phone.
With an
unlocked device you can purchase a new phone at any time and still stay with the same carrier and contract.
I purchased this phone when I signed up with my carrier but it doesn’t meet my needs.
With an
unlocked device
you can stay with the same carrier and have a phone that meets your needs.
I have damaged my phone but am not eligible for an upgrade.
You can purchase an
unlocked device and stay within your contract.
I travel
internationally but my phone doesn’t.
All
unlocked devices are tri-band and with an
international plan will work during your travels.
If I purchase an
unlocked phone, are there accessories I need?
If you purchase an
unlocked phone, you will still need to own a SIM card and have access to a carrier network. You can usually obtain a SIM card for free from a carrier retail location.
I am interested in Internet calling.
Unlocked phones equipped with WiFi, such as the Nokia E71 and the Nokia N95 8GB have built in WiFi; therefore, VoIP services such as Skype will work through your phone.