Unlocked cell phones
Unlocked cell phones allow user to swap the SIM card. SIM card are small memory chips attached with the cell phones working on the GSM network. The manufacturers of the cell phones do not lock the phones. The network providers or the carriers for example, the AT &T Mobility, T-Mobile, Vodafone etc. which operates on GSM network uses the locking software on the cell phones so that these phones accept only specific SIM cards.
You can buy unlocked cell phones or get the card-enabled cell phones unlocked by any third party vendor but the unlocked cell phones does not always work properly as it still may retain some of the proprietary information and display the original branding and may not support features of the new carrier. Code for unlocking the cell phone is available on the forums on internet, you can upload those but it is recommended only for advanced users.
In some European and Asian countries like Belgium and Singapore locking a cell phone is not allowed. But in USA there is no such regulation though many subscribers will unlock your cell phone after the contract period. UK is on the extreme end where the subscribers need not unlock the phone even after end of the contract period. The subscriber locks the cell phone to keep the customer tied to their service; in exchange they provide the cell phone at a much lower price than the actual retail price of the mobile phone. Cell phones could be unlocked by entering a special code provided by your carrier. Once you enter the right code, it will display some message like 'Network Unlocked'. A master code or network code key generally removes all SIM locks from the cell phones. Basically unlocked cell phones are those where no special locking firmware is installed or the firmware is removed by codes.
It is always advisable to take help of your vendor for unlocking your cell phone. Buying a cell phone cheap with a plan and then unlocking it often proves to be more profitable to a customer, this has created third party vendors unlocking cell phones for a fee. It is definitely better take a professional help for unlocking your cell phone because most phone have some built in security measures which will hard lock the phone if you enter the unlock code too many times, usually four times.
Unlocked cell phones are in great demand because if you can unlock a cell phone you can also use it with a different SIM card. It comes out to be a cheaper open particularly when you are traveling abroad and temporarily need use a foreign network. In such situation, you just buy a cheaper prepaid subscription and put the temporary SIM inside your cell phone. Buying unlocked cell phones are another option but unlocked cell phones are sold at higher price.
Many people opines that using unlocked cell phones are just fine though some problems remain like text messaging does not work etc. in the beginning but inserting proper code, you can make it work. Though buying unlocked cell phones are cheaper and there are many advantages but there are still some hurdles too. The most obvious being this works only for GSM technology. In GSM mobiles the subscriber and network information is stored in a SIM card and the phone is SIM locked. If you have unlocked cell phones you can take out the old SIM and insert the new one. But it is not so for CDMA based networks. The CDMA phones keeps the information in memory which locks the phones with specific network leaving you with no option but change the phone. Unlocked cell phones are more popular for the simplicity of working.
