A cell phone that doesn't have a SIM (subscriber identify module) card stores all of its data in internal memory. You can clone a cell phone that stores the data in its own memory so that the second can be used instead of the first by accessing a hidden menu configured in the operating system. All the 3G (third-generation) cell phones that store their data internally have this hidden menu.
Go to a website that provides the access number to your 3G cell phone--for example, the Cell Phone Hacks website (see Resources). Enter your cell phone's name and model number in the appropriate text fields on the web page and press the "Enter" button. Write down the number and access information that will let you reach the hidden menu on the cell phone. Write down the "Number Changer" number that is also presented on the web page.
Access the hidden menu on the 3G cell phone by following the information that was written down. Enter the number that was written down in the text field that requests it in the hidden menu. Press the button requested on the cell phone to enter the hidden menu's programming screen. Select the "Information" screen.
Write down the "ESN" (Electronic Serial Number) that is presented on the hidden menu's information page. Exit the hidden menu.
Access the hidden menu on the duplicate 3G cell phone that you want to become a clone of the first--the procedure will be the same since both phones are identical. Select the "Information" screen.
Delete the "ESN" number presented on the hidden menu's information page. Enter the "ESN" number that was written down. Exit the hidden menu.
Access the hidden menu again. Enter the "Number Changer" number to access the "Phone Number" screen. Delete the phone number in the text field on the screen. Enter the phone number of the first phone in the text field. Exit the hidden menu.