International Journal of Scientific and Research Publication (IJSRP)
During the invent of Code Division Multiple Access (CDMA) mobile phones, no one could ever imagine a day would arise, when more than a billion mobile phones would be manufactured and used worldwide over a short span of time. Each mobile phone is required to have a unique serial number burned into its chips in order to prevent fraud. Without a unique number, the phone can't be sold. So initially in order to identify phones on a network, engineers developed a 32-bit code called the Electronic Serial Number (ESN). This code was used for billing and to make sure the right call went to the right phone.