What Is The Master unlock Security Code Samsung SGH-C140 phon

Cell phones are limited to a certain cellular network. This means they are designed to work only with the SIM (Subscriber Identity Module)s for that particular network. Some phones can be unlocked, which allows them to be used on any network. Samsung phones have a unique unlock code which can be used to free them from their mobile phone operator

About Locked Phones
1. Only a few companies have lockable phones--T-Mobile, AT&T and Cingular. Mobile companies lock down phones to keep their customers from using their phones if they switch to other services. This keeps you from using the BlackBerry that you bought at Cingular with the T-Mobile network if you switch. Phones are normally only unlocked at the mobile company's store, but it is perfectly legal to unlock your own. The only exception to this is if your phone contract specifically states that you are not to alter or modify your phone, and that the phone is the property of the provider, not you.
Unlock Your Samsung Phone
2. According to AskStudent.com, go to the Nokia Free Unlock Codes Calculator and download the program (see link in References). Install and run the Calculator. Find the manufacturer and model for your Samsung cell phone, then enter your IMEI (International Mobile Equipment) number. Find the IMEI number for your phone by dialing *#06#. Choose your country and cell phone provider and enter your number. A list of codes will appear. Try them until you find one that works for you.
Test Your Phone
3. Have a friend with a different network attempt to use his SIM card on your phone. If it works and your phone identifies her as the owner, your phone has successfully been unlocked. If not, go back and try another code. Also, check the information you put into the Calculator. If you made any errors, you might have gotten the wrong code for your phone. Correct the errors and try again.