Updating a tmobile sidekick phone
For example, in South America, the 850 MHz band is in common use, but others may not be available.
It is advisable to check on which bands the phone uses, and which bands are available in given travel destinations.
One way to get a phone without proprietary settings is to buy it new from a third party vendor in its original, unlocked state.
People also don't need to wait for a contract to expire to buy a new phone; they can remove the SIM (Subscriber Identification Module) card from an existing phone and insert it into a new one when they are ready for a replacement.
Most carriers on the CDMA network do not, as of 2012, use card-enabled phones; instead, subscriber information is stored in the cell phone's memory, which means it cannot be transferred to another phone.
The CDMA equivalent of the SIM card — the R-UIM — is used in some parts of Asia, but it's not likely to spread more widely.
Carriers may include such features only on locked phones, which use their proprietary software and settings.
Some carriers offer free calling to a number of contacts or one-button access to certain features that can only be used on locked phones.